Composed by Andrew Lloyd Webber, Cats is based on Eliot's Old Possum's Book of Practical Cats (1939), which the composer recalled as having been a childhood favorite. The songs of the musical comprise Eliot's verse set to music by the composer, the principal exception being the most famous song from the musical, "Memory", for which the lyrics were written by Trevor Nunn after an Eliot poem entitled "Rhapsody on a Windy Night". Also, a brief song entitled "The Moments of Happiness" was taken from a passage in Eliot's Four Quartets. An unusual musical in terms of its construction, the overture incorporates a fugue and there are occasions when the music accompanies spoken verse. The set, consisting of an oversized junk yard, remains the same throughout the show without any scene changes. Lloyd Webber's eclecticism is very strong here; musical genres range from classical to pop, music hall, jazz, rock and electro-acoustic music as well as hymnal songs such as "The Addressing of Cats".
Cats premiered in the West End at the New London Theatre on 11 May 1981. There was trouble initially as Judi Dench, cast in the role of Grizabella, snapped a tendon during rehearsals prior to the London opening. The role of Grizabella was subsequently taken over by Elaine Paige. The role was beefed up for Paige and the song "Memory" (originally to be sung by Geraldine Gardner in the role of the red cat Bombalurina) was given to Paige. The musical was produced by Cameron Mackintosh and Lloyd Webber's Really Useful Group, directed by Trevor Nunn, with associate director and choreographer Gillian Lynne, design by John Napier, and lighting by David Hersey. It played a total of 8,949 performances in London. Its final performance in London's West End was on its 21st birthday, 11 May 2002, and broadcast on a large screen in Covent Garden to the delight of fans who could not acquire a ticket for the final performance. It held the record as London's longest running musical until 8 October 2006, when it was surpassed by Les Misérables.
The original 1981 London cast of Cats.
The show made its debut on Broadway on 8 October 1982, at the Winter Garden Theatre with the same production team. On 19 June 1997, Cats became the longest-running musical in Broadway history with 6,138 performances. It closed on 10 September 2000, after a total of 7,485 performances. Its Broadway record was surpassed on 9 January 2006 by The Phantom of the Opera. It remains Broadway's second longest-running show in history. Lloyd Webber stated that when the original show was produced, it cost £900,000, but on Broadway, it cost $5,000,000.
In 1998, Lloyd Webber produced a video version of Cats, based upon the stage version, starring Elaine Paige, who originated the role of Grizabella in London; Ken Page, who originated Old Deuteronomy on Broadway; Sir John Mills as Gus; Michael Gruber as Munkustrap; John Partridge as The Rum Tum Tugger; Jo Gibb as Rumpelteazer with many of the dancers and singers drawn largely from various stage productions of the show. It was directed by David Mallet, with choreography and musical staging by the show's respected original creator Gillian Lynne in London's Adelphi Theatre, and was released on VHS and DVD, as well as broadcast on television worldwide. Andrew Lloyd Webber and others on the production team for the film wanted to keep the feeling that viewers watching the film could still get the sense of seeing the show live, by having all views be facing the stage, therefore, getting multiple views of the set, but still feel like the viewer is part of a live audience, with several close-ups. Beyond the productions in Britain, the U.S., Canada, and Australia, the musical has been produced professionally in Hungary, Austria, and Japan, 1983; Sydney and Toronto, 1985; Germany, 1986; France, 1989; Mexico, 1991; Netherlands, 1992; Argentina, 1993; Hong Kong, 1994; Spain, 2003; Poland and Czech Republic, 2004; Russia and Estonia, 2005; Israel, Taiwan, Thailand, South Korea, China and Finland, 2007; Singapore, Hong Kong, Dominican Republic, Norway, Sweden, South Africa, China, Italy, Bulgaria and Japan, 2009; and Brazil and the Philippines, 2010. Cats has been translated into over 20 languages. 
 Detailed synopsis
 Act I — When Cats are Maddened by the Midnight Dance
After the overture, the Cats gather on stage and explain the Jellicle tribe and their purpose (Jellicle Songs for Jellicle Cats). The Cats (who constantly break the fourth wall, in the musical) spot the human audience and explain how the different Cats of the tribe are named (The Naming of Cats). This is followed by a dance from Victoria the White Cat that signals the beginning of the Jellicle Ball and Munkustrap tells us that tonight is the night when Old Deuteronomy will choose a cat to be reborn into a new life on the Heaviside Layer.
Munkustrap appears and introduces Jennyanydots (The Old Gumbie Cat), a large tabby cat. She "sits and sits and sits" all day, while at night she rules over the mice and cockroaches, teaching various activities to them. Jennyanydots finishes, greets the other cats, but is interrupted. The music instantly changes, and The Rum Tum Tugger makes an extravagant entrance (The Rum Tum Tugger). The Tugger is a Tom with a wild mane and leopard spots on his chest. He is very fickle and unappeasable, "for he will do as he do do and there's no doing anything about it".
A shabby old grey cat stumbles out and looks around. It is Grizabella. All the cats back away. The cats sing of her saddened, unfortunate state (Grizabella: The Glamour Cat). Grizabella leaves and the music changes to a cheerful upbeat. Bustopher Jones, a fat cat in "a coat of fastidious black", appears (Bustopher Jones: The Cat About Town). Bustopher Jones is among the elite of the cats, and visits prestigious gentleman's clubs. A loud crash startles the tribe. Could this be Macavity? The cats run off the stage in fright. Hushed giggling signals the entrance of Mungojerrie and Rumpelteazer, a pair of near-identical cats. They are petty burglars, very mischievous, and they enjoy causing trouble for human families (Mungojerrie and Rumpelteazer).
Finally, the Jellicle patriarch, Old Deuteronomy, shows up (Old Deuteronomy). He is a large old Cat that "has lived many lives" and "married nine wives (And more, I am tempted to say – ninety-nine)". He is the one who will choose which Jellicle cat will go to the Heaviside Layer. In most productions, at this point, the cats perform a song (The Awful Battle of the Pekes and the Pollicles) for Old Deuteronomy. It is a story about two dog tribes clashing in the street and subsequently being scared away by the Great Rumpus Cat, a cat with flashing red eyes. After a few words from Old Deuteronomy on the destiny of Jellicle Cats and Pollicle Dogs, a second loud crash, presumably from Macavity, sends the alarmed cats scurrying. But Old Deuteronomy calls them back and the main celebration begins (The Jellicle Ball), in which the cats sing, dance and display their "terpsichorean powers".
After the Ball, Grizabella reappears and tries to dance, but her age and decrepit condition prevent her from doing so. Once again, she is shunned by the other cats, but that does not stop her from singing a short version of Memory.
 Act II — Why Will the Summer Day Delay — When Will Time Flow Away?
After the Jellicle Ball, Old Deuteronomy sings of "what happiness is", referring to Grizabella. This message naturally goes over everyone's heads, so he sends the message again and Jemima (or Sillabub, depending on the production) sings it for everyone to hear, (The Moments of Happiness). Gus — short for Asparagus — shuffles forward ('Gus: The Theatre Cat'). He is the cat that once was a famous actor but now he is old and "suffers from palsy which makes his paws shake". He is accompanied by Jellylorum, who tells of his exploits. Gus then remembers how he once played the infamous Growltiger, Terror of the Thames (Growltiger's Last Stand). He tells the story about the pirate's romance with Griddlebone and how he was overtaken by the Siamese and forced to walk the plank.
Back in the present, after Gus exits, Skimbleshanks is sleeping in the corner (Skimbleshanks: The Railway Cat), a cat who is unofficially in charge of the night train to Glasgow. He is very clever and very important because if he is gone "the train can’t start". Within his song, a whole locomotive train engine is assembled out of objects in the junkyard, with various cats spinning wheels, holding up the structure and lighting the headlights.
With a third crash and an evil laugh, the "most wanted" cat, Macavity appears. He is a "master criminal" and never is found at the scene of the crime. He is a horrifying looking cat and a "villain" of the Jellicle Tribe. Macavity's minions throw a net over Old Deuteronomy and capture him. As the other cats try to follow him, Demeter and Bombalurina sing what they know about Macavity, as they have had some sort of past with him (Macavity: The Mystery Cat). When they are finished, Macavity returns disguised as Old Deuteronomy. When revealed by Demeter, he fights with Munkustrap and Alonzo. Though he holds his own for a time, Macavity is overwhelmed by the two younger tomcats; as the rest of the tribe begins to gang up and surround him, he shorts out the stage lights and escapes in the confusion.
Rum Tum Tugger suggests that the cats find Mr. Mistoffelees (Magical Mr. Mistoffelees). Mr. Mistoffelees is black and small and can perform many feats of magic that no other cat can do. Mr. Mistoffelees performs his dance, which is the most intricate and challenging dance for any solo in the whole show. The magical cat restores the lights and brings back Old Deuteronomy, earning praise from all the cats. The Jellicle choice can now be made.
Old Deuteronomy sits down and Grizabella appears for the final time. Old Deuteronomy allows her to have a chance to address the cats. Her faded appearance and lonely disposition have little effect on her song (Memory). With encouragement from Jemima and Victoria accepting her always, the appeal succeeds and she is chosen to be the one to go to the Heavyside Layer and be reborn to a new Jellicle Life. (Journey to the Heaviside Layer). A large tire rises up with Old Deuteronomy and Grizabella. Once at the top Grizabella finishes the journey herself. Old Deuteronomy gives his closing speech to the human audience (The Ad-dressing of Cats) and the show comes to a close.
 Musical numbers
Overture – Orchestra
Prologue: Jellicle Songs For Jellicle Cats – The Company
The Naming Of Cats – The Company
The Invitation To The Jellicle Ball – Victoria, Quaxo, Munkustrap
The Old Gumbie Cat – Jennyanydots, Munkustrap, Bombalurina, Jellylorum, Demeter
The Rum Tum Tugger – Rum Tum Tugger, Company
Grizabella: The Glamour Cat – Grizabella, Demeter, Bombalurina
Bustopher Jones: The Cat About Town – Bustopher, Jennyanydots, Jellylorum, Bombalurina
Mungojerrie And Rumpleteazer – Mungojerrie, Rumpleteazer
Old Deuteronomy – Munkustrap, Rum Tum Tugger, Old Deuteronomy
The Awefull Battle of The Pekes and the Pollicles – Munkustrap,Company
The Song of the Jellicles – The Company
The Jellicle Ball – Orchestra
Grizabella, The Glamour Cat (Reprise) – Grizabella
Memory – Grizabella
The Moments Of Happiness/Memory – Old Deuteronomy, Jemima
Gus: The Theatre Cat – Asparagus, Jellylorum
*Growltiger's Last Stand, incorporating either 'The Ballad Of Billy M'Caw' or the Italian aria 'In Una Tepida Notte' – Growltiger, Griddelbone, Ghengis/Gilbert, the Siamese, the Crew
Gus: The Theater Cat (Reprise) – Asparagus
Skimbleshanks: The Railway Cat – Skimbleshanks, the Company
Macavity: The Mystery Cat – Demeter, Bombalurina
Macavity Fight – Macavity, Munkustrap, Alonzo
Mr. Mistoffelees – Quaxo, otherwise known as Mr. Mistoffelees, Rum Tum Tugger
Memory/Daylight – Jemima
Jellicle Choice – Munkustrap
Memory (Reprise) – Grizabella, Jemima
The Journey To The Heaviside Layer – The Company
Finale: The Ad-Dressing Of Cats – Old Deuteronomy
* Not featured in 1998 video
 Principal characters
These descriptions, in alphabetical order, are based on more recent versions of the show, although there are minor variations from production to production.
Asparagus / Gus – The theatre cat. One of the oldest tribe members. He was once an actor.
Bombalurina – A saucy red female. A Principal vocalist and dancer.
Bustopher Jones – A fat cat, a "twenty-five pounder." Dresses in a snappy tuxedo and spats. Respected by all, as the upper class "St. James's Street Cat". In most productions, the actor playing Gus also plays Bustopher, though in early productions the part was handled by the actor playing Old Deuteronomy.
Demeter – A very skittish female cat, principal vocalist.
Grizabella – The former Glamour Cat who has lost her sparkle and now only wants to be accepted. Grizabella left the tribe when she was younger to see the world for herself; she has experienced the harshness of the world and is a pariah in the cats' society.
Griddlebone – A fluffy white Persian cat. Growltiger's lover in Growltiger's Last Stand, where she sings The Ballad of Billy M'Caw or the mock Italian aria In Una Tepida Notte (depending on production) with Growltiger. Almost always played by the actress playing Jellylorum. She does not appear in productions which omit Growltiger's Last Stand.
Growltiger – A theatrical character Gus recalls playing in his youth, and who appears in Gus' memory of the production of Growltiger's Last Stand. In some productions he is portrayed as a vicious pirate; in others he is more of a parody of a pirate. Does not appear in productions which omit Growltiger's Last Stand.
Jellylorum – A female who watches out for the kittens, along with Jennyanydots. She has a close relationship with Gus. Named after T. S. Eliot's own cat. The actress who plays Jellylorum usually also plays Griddlebone in Growltiger's Last Stand.
Jemima – A kitten interchangeable with Sillabub, though Jemima is used in most international productions. She is the kitten who sings the Memory refrain in The Moments of Happiness for Old Deuteronomy. Jemima sings the happier parts of Memory, while Grizabella sings the more sad parts. Jemima is the youngest kitten in the tribe, and she wants to be a glamour cat just like Grizabella was, before Grizabella left the tribe to explore the outside world.
Jennyanydots – The old Gumbie cat. She sits all day and rules the mice and cockroaches at night, forcing them to undertake helpful functions and creative projects, to curb their naturally destructive habits.
Macavity – the show's only real villain. The character is a literary allusion to the Sherlock Holmes character Professor Moriarty. Usually played by the same actor as Plato or Admetus.
Mr. Mistoffelees – A young black tom with magical powers, which he doesn't fully control. His signature dance move is "The Conjuring Turn", twenty-four fouettés en tournant. He's sort of a rascal. He's a bit of a child prodigy of the tribe. Brilliant at what he does but a little wacky at the same time. He's not really an adult yet, but he's not a kitten. So he's in an in-between stage. He doesn't quite know how to use his magical powers yet, but he's learning. He has a lot of adolescent qualities. In the UK production, Mistoffelees has an alter-ego named Quaxo, who appears as a general chorus cat throughout the show, and is dressed slightly differently. Occasionally Quaxo is a separate character.
Mungojerrie – Half of a pair of notorious cat-burglars, with Rumpleteazer. Mungojerrie and Rumpleteazer are most commonly remembered for their featured dance number where at the end, they do a "double windmill" across the stage.
Munkustrap – The show's de facto narrator. A black and silver tom who is storyteller and protector of the Jellicle tribe. He is thought to be second in command after Old Deuteronomy.
Old Deuteronomy – The lovable patriarch of the Jellicle Tribe. He is very old and dignified.
Rumpleteazer – Female half of a pair of notorious cat-burglars, with Mungojerrie.
The Rum Tum Tugger – The ladies' tom. His temperament ranges from clownish to serious, and often sexual depending on the production; however, he is always flirtatious, and usually portrayed as a feline equivalent of Mick Jagger or Elvis Presley, and recognisable by his wild mane.
Skimbleshanks – The railway cat. An active orange tabby cat, who lives on the trains and acts as an unofficial chaperon to such an extent he is considered rather indispensable to the train and station employees.
Victoria – A pure white kitten gifted in dancing. The "official" Jellicle Ball begins with her solo dance. She also does a Pas De Deux with Plato during the Jellicle Ball. She is also the first cat/kitten to touch and accept Grizabella.
 Other characters
The more notable minor characters are as follows:
Admetus- a shy, ginger and white tom. The actor usually also plays the Rumpus Cat or Macavity.
Alonzo – A black and white tom cat in most productions; in the Broadway and early European productions, he was depicted as being a black and gold tabby. Sometimes considered the third in command after Munkustrap as he also fights Macavity.
Bill Bailey – Bill Bailey is a london chorus kitten interchangeable with Tumblebrutus. He is a playful young kitten, often performing acrobatics as well as being a strong dancer. His costume is patchy browns on a white base, suggesting he is a Bi-colour tabby and white.
Carbucketty – The name was one of T. S. Eliot's ideas for cat names for a "knockabout cat." Sometimes interchangeable with the character of Pouncival.
Cassandra – A mysterious brown and cream Abyssinian queen, with a braided tail.
Coricopat – Male twin to Tantomile. Coricopat and Tantomile are often portrayed as psychic cats, as they sense the presence of danger before it becomes apparent to the other characters.
Electra and Etcetera – Tabby kittens who are fans of Rum Tum Tugger. Electra is dark and quieter, Etcetera is paler and hyperactive.
Exotica – Chorus cat made for the 1998 film. Appears in few scenes and dance numbers.
Ghengis or Gilbert – The leader of the crew of Siamese cats who contribute to Growltiger's demise. Usually played by the actor who portrays Mungojerrie, Tumblebrutus or Coricopat.
George – A male chorus cat. In London productions Goerge played Rumpus Cat in the junkyard performance of "Pekes and Pollicles". George was also featured as part of Growltiger's "Raffish Crew".
Plato – Teenage male cat; the actor usually doubles as Macavity. He does a pas de deux with Victoria during the Jellicle Ball. Plato is somewhat interchangeable with Admetus.
Pouncival – a playful, tom kitten sometimes interchangeable with Carbucketty and often first understudy to Mr. Mistoffelees
Rumpus Cat – A spiky-haired cat with glowing red eyes, as mentioned in The Awefull Battle of the Pekes and the Pollicles, seen as a sort of superhero figure among the Jellicles. Does not appear in productions which omit the song The Awefull Battle of the Pekes and the Pollicles. Usually played by Alonzo or Admetus.
Sillabub, the Broadway version of Jemima. Sillabub was a name created for the American productions due to possible racist connotations to "Jemima". The Japanese, Australian (in particular the Brisbane cast, who have Jemima as just a dancer) and Swedish casts include both Sillabub and Jemima as different characters.
Tumblebrutus – A playful young adult cat. Tumblebrutus is a brown and white tabby, characterized by a large, flame-like brown patch over his left eye. This energetic young tom is featured in many dance numbers and has many featured solos throughout the show. He is the Broadway version of Bill Bailey.
Tantomile – Female twin of Coricopat. The name was created by T.S. Eliot for a "Witch's Cat".
Victor – Victor is a London chorus cat. He is cream and brown tabby markings and few distinguishing features. He featured as one of Growltiger's crew. The actor playing Victor was usually an understudy for Rum Tum Tugger and Munkustrap.