Status: Spanish champions Nickname: Los Blancos (The Whites)
THE LEGEND: The nine-time European champions love this competition like no other and you merely need to take a tour of their historic Bernabeu trophy room to appreciate that Champions League glory is their enduring dream each and every season.
However, more than a decade has passed since Real Madrid last tasted triumph in this competition, and that is far too long for this club to wait for the taste of more European glory. Real have also won two UEFA Cups, two Cup Winners' Cups and the 2002 UEFA Super Cup.
CALLING THE SHOTS: Jose Mourinho
The most-talked-about manager in world football is back for another crack at the competition he won with FC Porto in 2004 and Inter Milan in 2010, and few would back against this touchline master claiming the European crown with a third club.
Mourinho's success in recent years has changed the landscape of European football as he started a trend that has transformed the way clubs from all corners of the continent hire their tacticians. Clubs used to recruit former players with moderate coaching experience to patrol their touchlines, but Mourinho has shown that calling on the services of intelligent students of the game can be even more successful.
THE GAME PLAN: Mourinho is often criticised for employing ugly tactics, yet the tag is grossly unfair when pinned on a coach who oversaw a thrillingly successful Real Madrid title charge last season. A team that scores 121 goals in 38 league games can hardly be accused of being negative.
His Chelsea and Inter Milan teams were capable of producing thrilling football, but Mourinho's great skill is appreciating what is required for each individual occasion. If Barcelona are in town, controlled aggression replaces rampant boldness and, more often than not, the self-proclaimed "Special One" gets it right.
Mourinho long favoured a system with a lone striker, but he can employ two or even three attacking players on some occasions, with Cristiano Ronaldo given license to float wherever he sees fit. New signing Luka Modric will need to show some defensive qualities to complement his silky passing.
BIG HITTER: Cristiano Ronaldo
The panic button was hit across Madrid when this scoring machine suggested he was unhappy at the club amid rumours of a contract dispute, yet it is impossible to consider the prospect of Real allowing the player they paid £80 million to sign from Manchester United to leave anytime soon.
His brilliance last season was at the heart of Real's La Liga success, and while sections of the Bernabeu faithful get frustrated by his eagerness to take every free kick and try to steal the show himself, this Portuguese genius is worthy of the adulation that comes his way.
CAPTAIN FANTASTIC: Iker Casillas
The theory that goalkeepers do not make good captains has been disproved by Casillas, who has become a fine leader for club and country in recent years. Casillas has won two European titles in Real Madrid colours, with the first coming in 2000, when he became the youngest keeper ever to appear in a Champions League final, just four days after his 19th birthday. From that day forward, he has been recognised as one of the finest keepers in world football.
NEW KID ON THE BLOCK: Luka Modric
After many months of haggling and much rhetoric flying between Tottenham and Real Madrid, a £33 million deal for Croatian midfielder Modric to join the Spanish champions was finally hashed out in mid-August. "We didn't try to buy anyone other than Modric this summer as we already have a strong squad and he was the only player I needed to strengthen," said Mourinho, who has been a long-time admirer of this willowy playmaker.
SHOOTING STAR: Naco
Plotting a route into this settled and experienced Real Madrid side is no easy task for a novice, but Naco is viewed as one who could break into Mourinho's side if injury befalls his first picks. Capped by Spain at the under-21 level, he was included in the final squad for this Champions League adventure and may get a chance to play if Real get an opportunity to rest weary legs later in the group phase.
SECRET WEAPON: Michael Essien
In one of the more surprising moves of transfer deadline day, Mourinho was reunited with one of his Chelsea old boys, as Real Madrid agreed to a loan deal to bring this powerhouse midfielder to the Spanish capital.
At his best, the terrier who acquired the nickname of "The Bison" at Stamford Bridge was one of the finest central midfielders in the game, offering dynamism, great passing ability and the odd goal to boot. Sadly, injuries have weakened his abilities in recent years, but he provides quality backup to Mourinho's first-choice starters.
THE WEAK SPOT: Expectation weighs heavily on this club every time it takes to the field in the competition it likes to call its own, and that can work against the current Real Madrid players as they look to emulate the club's heroes of yesterday and win a 10th Champions League crown.
The Ronaldo contract dispute has the potential to destabilise this campaign, while the presence of high-profile former greats Kaka and Ricardo Carvalho is also unhealthy for Mourinho's team dynamic after a summer when the club tried and failed to offload both aging stars.
Then there is Mourinho himself, whose tendency to enforce media blackouts, fall out with match officials and generally get himself into trouble seems to be part of his makeup. When the going gets tough at the back end of the season, the Real Madrid boss would be wise to hold his tongue and stay out of trouble.
VERDICT Were it not for their perilously difficult group draw, Real Madrid would be joint-favourites for the European title with archrivals Barcelona. What has become clear in the past 12 months is that Mourinho has worked out a way of unsettling Barca and that could be crucial to his hopes of winning the Champions League for a third time.
Status: English champions Nicknames: Sky Blues, The Citizens
THE LEGEND: Manchester City's debut in the Champions League ended in desperate disappointment as they crashed out in the group stages last season, with nervous performances on home soil compounded by defeats against Bayern Munich and Napoli on their travels.
The club's finest hour in Europe came as it lifted the 1970 Cup Winners' Cup, beating Polish side Gornik Zabrze in a Vienna final witnessed by a mere 7,968 spectators. If City were to make it through to their first Champions League final in May, the crowd watching them at Wembley Stadium will be more than 10 times that modest figure.
CALLING THE SHOTS: Roberto Mancini
Mancini appeared to be about to come under intolerable pressure as he edged toward the end of his second full season as City boss with failure staring him in the face, yet a remarkable final twist in the Premier League title race transformed his career prospects in an instant.
City's wealthy and demanding owners may have considered a change of coach had failure been the final outcome in May, but they instead they handed Mancini a bumper new contract as they renewed their faith in his tactical abilities.
Mancini has been accused of being a little aloof with his players and is not one of those touchy-feely managers eager to put his arm around grumbling players. Instead, this smooth talker prefers to take a back seat, assume a leadership role and only makes his presence felt when the need arises.
THE GAMEPLAN: Mancini was lambasted for promoting negative tactics when he took over for Mark Hughes as City boss, with his safety-first approach in high-profile away games leading many to suspect he lacked the daring verve required to knock the Premier League's traditional giants off their perch.
All that changed last season, as his glittering array of attacking talent allowed him to field dynamic lineups, with creative players in midfield complementing front men who were rotated on a reasonably regular basis. Carlos Tevez and Sergio Aguero may be his first-choice strikers, but he has more than enough firepower in reserve with Eden Dzeko and Mario Balotelli waiting in the wings to shake it up from time to time.
The influence of Yaya Toure in midfield is crucial and his absence was sorely felt when he was unavailable for a spell last season, and City need to ensure they get the best out of the brilliant David Silva, who looked tired at the back end of last season.
BIG HITTER: Sergio Aguero
This Argentine super-striker came with a massive £38 million price tag attached to his collar in the summer of 2011, but he proved himself to be worth every penny as he scored goals aplenty in his first season at City and finished the campaign with the most iconic goal in the club's history, his 94th-minute title clincher against QPR.
Aguero was already a hero of the City faithful prior to that historic strike, with his work ethic, superb finishing ability and refusal to cause any off-field commotion, making him one of the best signings in this bold new era for Manchester's "other" club.
The son-in-law of Argentina football legend Diego Maradona, his success in adapting to the physical demands of the Premier League in double-quick time confirmed his class, and he has the ability to drive City's Champions League charge this season.
CAPTAIN FANTASTIC: Vincent Kompany
The obscene amount of money thrown at City to transform them into trophy contenders has left many of the game's purists feeling a little uneasy about the method of their success, yet few could deny Kompany his moment of glory as he lifted the Premier League trophy last season.
This classy Belgian centre back has been a part of the Eastlands "project" long before the mega-money investors transformed the image of the club, and his wholesome desire to succeed is a blast from the quickly forgotten days when City were about so much more than huge investment and exploding budgets.
NEW KID ON THE BLOCK: Javi Garcia
City made most of the transfer moves in the final hours of the summer window, and Garcia's arrival on deadline day was hailed by boss Mancini as a key moment in his side's season.
A defensive midfielder who can also slot in at the back if City suffer central defensive injury worries, Garcia arrived at City in a £16 million move from Benfica, and he is a player with plenty to prove at Eastlands after his stint at Real Madrid failed to confirm he is a player capable of shining at an elite club. A quality backup to Yaya Toure maybe, but Garcia has not come to City to warm the bench.
SHOOTING STAR: Mario Balotelli
This firebrand Italian appeared to have kicked his final ball for City when he was sent off at Arsenal in April, yet he remains a part of Mancini's plans and could provide the spark of genius required to ruffle the feathers of the Champions League elite.
Still only 22, Balotelli remains a mix of the brilliant and the crazy, and that concoction makes him one of the most fascinating characters in the modern game. His habit of producing the goods in the more high-profile games for club and country bodes well for City in their European adventure.
SECRET WEAPON: Scott Sinclair
City fought long and hard to strike a deal to ensure this young English winger would be part of their Champions League options, and Sinclair has the potential to make a difference with his pace and trickery on the wing.
Previously on the books at Chelsea, he shot to prominence in the Premier League with Swansea last season and City's eagerness to build a squad with an English influence meant he ticked plenty of boxes when their latest transfer target list was drawn up.
THE WEAK SPOT: City's failure to impress in last season's Champions League confirmed that even the most gifted and ambitious of newcomers to this competition can be blinded by the glare of its lights. We are about to find out whether they have learned the lessons of their Euro horrors last season.
Internal bickering never seems to be too far away at City, with the likes of Tevez, Balotelli and talismanic midfielder Toure liable to be linked with moves away from City if they are in a bad mood. Mancini has to hope the egos in his dressing room don't overinflate at the wrong moment if the tide turns against City in the highly competitive Group D.
City were exposed as being a little naive in the Champions League and lessons need to be learned from those setbacks. Might Mancini consider starting with just one striker and packing his midfield for the group-stage clashes with Real Madrid? It is certainly a possibility.
VERDICT: The tough nature of their opening group may serve City well if they plot a route to the knockout phase. They may not believe they are European contenders just yet, but seeing off Real Madrid, Borussia Dortmund and Ajax would alter their mindset for the better.
Status: Dutch champions Nicknames: Ajacieden, I Lancieri (The Lancers)
THE LEGEND: The Amsterdammers are one of the legendary names of European football, their golden reputation built on the three consecutive European Cups they picked up in 1971, 1972 and 1973.
When star front man Johan Cruyff left for Barcelona, the club subsequently fell off their lofty pedestal, but when the same Dutch icon returned as coach in the mid-1980s, the wheels began to turn again and in 1987 they scooped the Cup Winners' Cup.
With Louis van Gaal at the helm, Ajax continued to ride high, and under his uncompromising leadership they claimed both the 1992 UEFA Cup and the Champions League in 1995.
CALLING THE SHOTS: Frank de Boer
A long-serving Ajax defender who has swept the board in the Eredivisie since taking over from Martin Jol midway through the 2010-11 season, De Boer has plotted domestic dominance in each of the past two seasons -- a double triumph to sit very nicely indeed beside the five league titles he won as player at the club.
After hanging up his boots in 2006, he ran the Ajax youth team then became an assistant to Dutch national team boss Bert van Marwijk, notably playing a key behind-the-scenes role as the men in orange finished runners-up at the 2010 World Cup. His inaugural match at the Ajax controls was in the Champions League, his side running out impressive 2-0 winners away to AC Milan.
THE GAME PLAN: As a true believer in the Ajax faith, De Boer stays true to the club's time-honoured footballing creed: a 4-3-3 with the emphasis on adventure, a fluid passing game and width.
In contrast to when Martin Jol was in charge, De Boer encourages the fullbacks to push on, and long balls are no longer pumped forward aimlessly. Moves are built up patiently from the back and they look to circulate the ball at a crisp tempo.
The constructive strings tend to be pulled by central midfielder Theo Janssen and, to his left, Danish boy wonder Christian Eriksen. The former is especially important, an outstanding reader of the game, intelligent in his distribution and, all in all, a superior strategist.
Under De Boer, Ajax have introduced a Barcelona-like pressing game, looking to win back the ball as soon as it is lost. Their wingers are not glued to their flanks, and on the right, Haris Sulejmani cuts inside a great deal.
BIG HITTER: Christian Eriksen
One of the most exciting young talents in European football, this 20-year-old Dane is often mentioned in the same breath as the brilliant Laudrup brothers (Michael and Brian), and he does boast the same speed, dribbling ability and delicate creativity as those Scandinavian superstars of yesterday.
His one weakness is a certain lack of physical stature, and that is probably the reason he has not yet made the switch to a more high-profile league.
A teenage prodigy with the Odense club and Danish youth teams, he had virtually every leading continental club on his trail but eventually chose to move to Ajax in 2008, citing their reputation as youth development experts. An Ajax first-teamer for the past 2 1/2 years, he was voted Denmark's player of the year for 2011.
CAPTAIN FANTASTIC: Siem de Jong
This dynamic attacking midfielder or deep-lying striker was appointed skipper following the sale of Belgian central defender Jan Vertonghen to Tottenham.
A product of the Ajax youth ranks, the 23-year-old might not be the quickest, but what he does have going for him is his above-average football intelligence, perfectly timed dashes into space, aerial prowess and goal-scoring touch with either foot.
He comes from a sporting family, as both of his parents were international volleyball players and his younger brother Luuk currently stars up front for Netherlands as well as Borussia Monchengladbach in Germany. Siem has also won full caps for the Oranje, making his debut back in August 2010.
NEW KID ON THE BLOCK: Ryan Babel
This season will be crucial for this Netherlands winger/striker, who after five hugely disappointing campaigns with Liverpool and Bundesliga outfit Hoffenheim has opted for a career relaunch at his old club Ajax, the place where he learned his football and spent three years as a regular.
Capped 42 times for Netherlands and a European champion with the under-21s in 2007, he was so keen to leave Hoffenheim that he bought out the three remaining years on his contract.
Speedy and full of guile, the 25-year-old's experience of the Champions League with both the Amsterdammers and Liverpool should be just as useful in the coming months as his pace and trickery.
SHOOTING STAR: Daley Blind
The son of former Ajax defender and coach Danny Blind, this 22-year-old is a chip off the old block, a very composed and technically sound left back or libero. He came through the Ajax youth ranks, making his Eredivisie debut in 2008 at the age of only 18.
As a teenager, Blind was reported to be attracting interest from several leading English and Spanish clubs, but he wisely chose to remain with Ajax and continue his development at one of the best youth systems in world football. He has represented Netherlands at various levels from under-17 to under-21, and was once sent on loan to Groningen to round him out as a top-flight player.
SECRET WEAPON: Kolbeinn Sigthorsson
A multitalented young Icelandic striker signed in a £4.1 million deal from AZ in the summer of 2011. Unfortunately, he broke his ankle early on last season and only returned to the fray as the campaign was drawing to an end.
The 22-year-old has many strings to his bow, not least his physical presence, ability to serve as a frontline pivot, good movement and, of course, his eye for goal.
This Iceland international first came to prominence during the 2010-11 Eredivisie season, bagging no fewer than 15 goals. A number of elite English sides and Borussia Dortmund were ready and willing to bring him on board, but his heart was set on Ajax.
THE WEAK SPOT: The Amsterdammers can, at times, play too intricately, wanting to walk the ball into the back of the opposition net. Dictating in the Eredivisie is one thing; forcing the issue against individually stronger players in the Champions League another.
Frank de Boer has had to rebuild his back line following the recent departures of key men Vertonghen and right back Gregory van der Wiel. Ajax are not particularly comfortable when games turn physical or downright ugly.
VERDICT: Their youngsters will have to grow up very quickly indeed in the "Group of Death." Progress is unlikely.
Status: German champions Nicknames: BVB, Schwarz-Gelben (Black-and-Yellows)
THE LEGEND: Their finest hour came in May 1997, when they claimed their one and only Champions League title with a 3-1 victory in the final over red-hot favourites Juventus.
Cup Winners' Cup victors way back in 1966 -- beating Liverpool 2-1 in the final after extra time -- the Ruhr club suffered their most embarrassing continental competition reverse in the 1987-88 UEFA Cup, humbled 5-0 by Club Brugge in a second-round, second-leg tie.
CALLING THE SHOTS: Jurgen Klopp
Just beginning his fifth season in charge, the charismatic 45-year-old has certainly worked a miracle since arriving from Mainz in the summer of 2008, transforming a team very much in the doldrums into the top footballing force in the country as they won the Bundesliga two seasons ago and a domestic double last time around. What's more, he has done it the hard way, basing his success not on the chequebook but on his ability to mould, motivate and organise a group of relatively inexpensive young players.
Always passionate and exuberant in the technical area, Klopp's greatest asset is probably his skill as a communicator. Whatever the circumstances, he always finds the right words to keep his charges hungry and focused and, though relaxed and jovial by nature, he also has an authoritative and demanding side to him. A much-respected TV pundit during World Cups or European Championships, he both talks and directs a good game.
THE GAME PLAN: At the heart of the Dortmund modus operandi is an aggressive high pressing game allied to lightning-quick transitions from defence into attack. When firing on all cylinders, they are a whirlwind of activity, imagination and explosiveness, a high-octane fiery bundle that the opposition struggles to extinguish.
They are particularly sharp and snappy on the ball in the middle of the park, and whether it be wide midfielders Jakub Blaszczykowski and Kevin Grosskreutz or attacking fullbacks Lukasz Piszczek and Marcel Schmelzer, they set great store in penetrating on the flanks.
BIG HITTER: Robert Lewandowski
This Poland striker took quite a long time to settle in following his move from Lech Poznan two years ago, but if his first
season at the Westfalenstadion was a slow burner, he really got his act together last term, ending the campaign as the club's top scorer in the Bundesliga with 22 goals.
The complete front man, Lewandowski combines a wonderful first touch, clever movement, dribbling prowess, aerial threat, glacial-veined finishing and, last but by no means least, the ability to pull deep and link the play. The all-important question is how committed he is to the Dortmund cause: Rumours persist that he has become unsettled by talk of a switch to the Premier League.
CAPTAIN FANTASTIC: Sebastian Kehl
An experienced and reliable defensive midfielder/libero who serves as a rock-solid counterpoint to all the young guns on the team. In his 12th year as a Dortmunder, he signed from Freiburg midway through the 2001-02 season.
Capped on 31 occasions for Germany, he was a member of the Nationalmannschaft squad at both the 2002 and 2006 World Cups. After a frustrating four-year spell battling an assortment of injuries, he is now playing better than ever.
NEW KID ON THE BLOCK: Marco Reus
Bought from Borussia Monchengladbach for a cool £16 million, this winger, attacking midfielder or second striker is quite simply the most exciting young prospect in the German game today, and following a brilliant 2011-12 for Gladbach in which he provided 18 goals and 11 assists, he was deservedly voted the country's player of the year. How Germany coach Joachim Low must regret not using him from the start of the ill-fated Euro 2012 semifinal loss to Italy.
Quick and instinctive, the 23-year-old had many other suitors (Bayern Munich, Real Madrid, Inter Milan and Manchester City to name just a few), but Reus eventually plumped to follow his heart, agreeing to a deal with hometown club Dortmund.
SHOOTING STAR: Leonardo Bittencourt
Thanks to a string of eye-catching performances in the 2. Bundesliga with Energie Cottbus last season, the teenage creative midfielder had the great and the good of the Bundesliga fighting it out to sign him, eventually throwing in his lot with the reigning champions.
He is very much the product of two distinct cultures, born and raised in Eastern Germany by Brazilian parents. Indeed, football is in the Germany under-19 international's blood, his father Franklin once being a talented front man with top Rio team Fluminense as well as Cottbus.
SECRET WEAPON: Julian Schieber
A highly promising 23-year-old striker or left-sided attacking midfielder recruited this summer from Stuttgart. In theory, he has been
brought in to provide cover in the final third, but with his wholehearted style, he could make quite an impact from the bench.
Dortmund's interest in him can be traced to the two fine goals he scored against them in a 4-4 Bundesliga draw last term.
THE WEAK SPOT: As proved by the "wait and see" approach that helped them to a hard-fought 1-0 league victory against archrivals Bayern Munich last season, Dortmund can go tactical if they wish and yet, for the most part, they prefer to grab a match by the scruff of the neck. This naivety may prove harmful to them in the cold and calculated world of the Champions League.
Time will tell if they can fill the creative and goal-scoring void left by Shinji Kagawa, who joined Manchester United during the summer. They lack strength in depth in both fullback positions. If Piszczek or Schmelzer are laid low, they have problems.
VERDICT: After flopping in the Champions League group phase last season, this most spirited of sides will be going all out to set the record straight. Expect Klopp's side to have learned their lessons.