The novel opens with 15-year-old Alex and his gang members (known as "droogs") Pete, Georgie and Dim, who roam the streets at night, committing crimes that include rape (the "old in out, in out"), shoplifting, and violence (ultra-violence) for fun. In contrast to Alex's love for wrong-doing and cruelty, he also has a passion for classical music, Beethoven's Ninth Symphony being his favourite piece.
Essentially, the first part of the novel is a character study of the protagonist. We learn that Alex and his "droogs" (Russian for friend), have their own dialect known as nadsat, and their own hierarchy, in which Alex is the leader. Although they are all "droogs", Alex seriously resents Dim for his stupidity and constantly picks on him. There is a general disregard for the law and for older generations — creating an image of a youth movement that is taking control of this fictional future.
Part 1 involves Alex reflecting on his illegal activity. After drinking narcotic-laden milk at the Korova Milk Bar, Alex and his droogs ridicule and beat an old man, tearing up his books. They then rob a sweet shop, beating up the owner and his wife and then proceeding to the 'Duke of New York' pub, where they bribe a group of elderly alcoholic women into vouching for them by buying them food and drinks with their ill-gotten gains. After leaving, Alex and his droogs ridicule and beat an old drunken vagrant, and come across a rival gang lead by Billy Boy at a deserted power station. A fight between the two gangs ensues, with Alex and his droogs emerging victorious and leaving before the police arrive. They then steal a Durango '95 sports car for a reckless drive into the countryside and finally end up at HOME. That is, the name of the home that belongs to a reclusive writer named F. Alexander. The gang use their cunning and force to invade the house, savagely beating the writer, tearing up his written work (entitled "A Clockwork Orange"), and brutally raping his wife. Afterward, back at the Korova, there is a moment of tension among the four when Alex strikes Dim for ridiculing a woman as she sings a classical piece that moved Alex. The other droogs, Pete and Georgie, manage to keep the peace between them. Thus the group heads home. Alex returns to his home at a tower block, where his mother and father have factory jobs, and climaxes the evening by listening to classical music on his expensive stereo.
The following morning, after giving his mother an excuse for a need to miss school, Alex is visited by P.R. Deltoid, the social worker assigned to his case, who has heard word about Alex's doings the previous night. Deltoid warns Alex that if he gets in trouble again, he'll be sent to prison. Alex assures Deltoid he won't. While skipping school, Alex picks up two girls in a record shop, takes them home, and has sex with them both by getting them intoxicated. Sitting down at dinner, Alex's father asks his son about his "night job". Alex gives him a weak excuse, and then a generous portion of his "salary" to compensate. The earlier tension within Alex's gang deepens however, as Alex finds his droogs waiting for him outside his house. Alex learns that his droogs, particularly Georgie and Dim, are no longer fully satisfied with him as their leader, suggesting a "new way", and that they should drink "moloko plus" before they discuss it. Although he is slightly threatened, he deals with the problem by fighting and beating the two, slashing Dim's wrist and demonstrating his leadership and unwillingness to be overthrown. That night, the gang perpetrates another home invasion. When confronted by the owner, an elderly woman, Alex strikes her with a medium sized art sculpture, apparently rendering her unconscious. He soon hears police sirens, and attempts to flee. His droogs seize their opportunity to betray Alex, however, and Dim lashes him across the face with a chain (which Dim uses as a weapon), leaving his vision temporarily impaired and unable to escape from the police who arive shortly thereafter. Soon after his interrogation, Alex learns that the woman he struck with the statue died as a result of her injuries. Alex is convicted for her murder and sentenced to fourteen years in prison.
After helping to kill (although accidentally) a fellow prisoner in his cell, Alex is selected to become the subject in the first full-scale trial of the Ludovico Technique. The technique itself is a form of aversion therapy, in which Alex is given a drug that induces extreme nausea while being forced to watch graphically violent films for two weeks. Strapped into a seat, his head clamped and his eyes held open with specula, Alex has no choice but to watch the films. One of the films has a soundtrack of Alex's beloved Beethoven's Ninth Symphony, and though he pleads with them to remove the music, they refuse, saying that it is for his own good and that the music may be the "punishment element".
A few weeks later, he is presented to prison and government officials as a successfully rehabilitated member of society and released. The treatment has left him unable to perform, or even think about, any kind of violent action without becoming severely ill. He soon learns just how well it worked when he finds he cannot even defend himself against an attacker when necessary. The clinicians demonstrate the treatment's effectiveness in front of an audience, including the prison chaplain who was opposed to Alex's "treatment": a man taunts and abuses Alex who is rendered helpless to defend himself, as each time he tries he becomes nauseated. Then a beautiful, naked woman is shown to him, but Alex is unable to think of touching her without feeling ill.
Alex falls into the hands of Mr. Alexander, the husband of the woman he raped at the beginning of part one. Mr. Alexander was apparently crippled in the initial assault and is now confined to a wheelchair, and his wife is now deceased, due to an illness he blames on the rape. Since Alex was wearing a mask during the earlier assault, Alexander does not recognise him as the attacker. Recognising Alex's photo from the newspaper, Mr. Alexander's political activist friends decide to use him as a weapon against the government by turning him into a poster child for the victims of fascism; they play classical music in the room beside his, triggering the maddening effect of the Ludovico treatment. Driven to insanity by the music, Alex jumps from his bedroom window in an attempt to end his life.
Alex wakes up in a hospital, where he learns that the government, trying to reverse the bad publicity it incurred in the wake of Alex's suicide attempt, has reversed the effects of the Ludovico treatment and have offered him a well paying civil service job. His parents take him back in, and Alex happily ponders returning to his life of ultra-violence.
In the final chapter, Alex finds himself half-heartedly preparing for yet another night of crime with a new trio of droogs. After watching them beat an innocent stranger walking home with a newspaper, he begins to feel bored with his life of violence. He abandons the gang then has a chance encounter with Pete, an old droog who has reformed and married. Alex begins contemplating giving up crime himself to become a productive member of society and start a family of his own, while reflecting on the notion that his own children will be just as destructive-- if not more so-- than he himself.
The book is divided into three parts, each containing seven chapters. Burgess has stated that the total of 21 chapters was an intentional nod to the age of 21 being recognised as a milestone in human maturation. The 21st chapter was omitted from the editions published in the United States until 1986. The film adaptation, which was directed by Stanley Kubrick, was based on an early American edition of the book and ends prior to the events of the 21st chapter. Kubrick claimed that he had not read the original version until he had virtually finished the screenplay, but that he certainly never gave any serious consideration to using it.
Burgess wrote in introduction to the 1986 edition, titled A Clockwork Orange Resucked, that a creature who can only perform good or evil is "a clockwork orange — meaning that he has the appearance of an organism lovely with colour and juice, but is in fact only a clockwork toy to be wound up by God or the Devil; or the almighty state."
In his essay "Clockwork Oranges"², Burgess asserts that "this title would be appropriate for a story about the application of Pavlovian, or mechanical, laws to an organism which, like a fruit, was capable of colour and sweetness". This title alludes to the protagonist's positively conditioned responses to feelings of evil which prevent the exercise of his free will.
In the first edition of the book, no key was provided, and the reader was left to interpret the meaning from the context.
Droogism refers to the commission of a crime for the sole sake of committing a crime, without material gain or benefit; robbery and kidnapping with the intent to demand ransom, for example, do not qualify as droogisms, as they are committed with the intention of some sort of material benefit for the perpetrator.
The term "Ultraviolence", referring to excessive and/or unjustified violence, was coined by Burgess in the book, which includes the phrase "do the ultra-violent." The term's association with aesthetic violence has led to its use in the media.
Excerpts from the first two chapters of the novel were dramatised and broadcast on BBC TV's programme Tonight, 1962 (now lost, believed wiped).
After Kubrick's film was released, Burgess wrote a Clockwork Orange stage play. In it, Dr. Branom defects from the psychiatric clinic when she grasps that the aversion treatment has destroyed Alex's ability to enjoy music. The play restores the novel's original ending. One of Alex's early victims, a bearded trumpeter who plays "Singin' in the Rain" at the Korova milkbar, is modeled on Kubrick.
In 1990, a second play, titled A Clockwork Orange 2004, was written for the Royal Shakespeare Company. It makes no references to the film version, yet does away with the novel's ending. The performance was scored by Bono and The Edge of U2. In 2001, UNI Theatre (Mississauga, Ontario) presented the Canadian premiere of the play under the direction of Terry Costa. In 2002, Godlight Theatre Company presented the New York Premiere adaptation of Anthony Burgess's 'A Clockwork Orange' at Manhattan Theatre Source. The production went on to play at the SoHo Playhouse (2002), Ensemble Studio Theatre (2004), 59E59 Theaters (2005) and the Edinburgh Festival Fringe (2005). While at Edinburgh, the production received rave reviews from the press while playing to sold-out audiences. The production was directed by Godlight's Artistic Director, Joe Tantalo.