Time Magazine included the novel in its TIME 100 Best English-language Novels from 1923 to 2005.
The book's epigraph is:
One Flew Over the Cuckoo's Nest was a direct product of Kesey's time working the graveyard shift as an orderly at a mental health facility in Menlo Park, California. Not only did he speak to the patients and witness the workings of the institution, he received electroconvulsive therapy and took psychoactive drugs (notably LSD, psilocybin, mescaline and DMT) as well as the same drugs as the patients as part of government-sponsored drug experiments. From this, he became sympathetic toward the patients and from then on garnered enough information to write a book about mental illness and psychiatric health care.
Narrated by the gigantic but docile Columbian Indian "Chief" Bromden, who has pretended to be a deaf-mute for several years, this story focuses on the antics of the rebellious Randle Patrick McMurphy, a happy-go-lucky transferee from a prison workfarm to a mental hospital. Having been found guilty on a battery charge, McMurphy fakes insanity to serve out his sentence in the hospital. The all-male asylum is based upon the old Pendleton, Oregon asylum (now the Eastern Oregon Correctional Institution). With little medical oversight, the hospital ward is run by the buttoned-up, tyrannical Nurse Ratched (or as Bromden calls her, "the Big Nurse") and her black orderlies, whom the Chief portrays as resentful "black boys."
McMurphy constantly antagonizes Nurse Ratched and upsets the routines. Betting on himself, McMurphy tries and fails to lift a heavy shower room control panel. He runs a card table, captains the ward's basketball team, comments on Nurse Ratched's figure, incites the other patients on the ward to conduct a vote on watching the World Series on television, and organizes a supervised deep sea fishing trip. The Chief, opening up to McMurphy due to the latter's rebellion, reveals late one night that he can speak and hear. McMurphy presents a discipline problem and challenge to Nurse Ratched's authority, and the two become engaged in a power struggle. One night, after bribing the night orderly, McMurphy breaks into the pharmacy and smuggles bottles of liquor and two prostitute girlfriends onto the ward for a party, including some of the patients. McMurphy persuades one of the women to seduce Billy Bibbit, a timid, boyish patient, with a terrible stutter and no experience with women. Neglecting to clean up before the morning shift arrives, McMurphy and the other patients fall asleep. The staff returns and discovers the aftermath of the party. The staff finds the night orderly and the rest of the ward, in the minds of the patients, comically askew. Nurse Ratched finds Billy Bibbit and the prostitute in each other's arms, partially dressed, and admonishes him. Billy asserts himself for the first time, answering Nurse Ratched without stuttering. Ratched calmly threatens to tell Billy's mother what she has seen. Billy has an emotional breakdown, and once left alone in the doctor's office, slits his own throat and bleeds to death. Nurse Ratched blames McMurphy for the loss of Billy's life. Infuriated at what she has done to Billy, McMurphy attacks her and attempts to strangle her to death. He fails and is removed to the Disturbed ward, where he undergoes a lobotomy.
When McMurphy returns, he is wheeled onto the ward on a bed, in a near-vegetative state similar to its most elderly patients. The Chief realizes that if other patients see McMurphy in that condition, Nurse Ratched will have ultimately "won", demoralizing the patients who were only beginning to assert themselves as men because of McMurphy's influence. The Chief smothers McMurphy with a pillow to suffocate him during the night. He does this so that McMurphy can die with dignity rather than lie there as a representation of what happens when one tries to buck the system. Chief Bromden then lifts and carries the shower room control panel to the window, throws it through the window and escapes. Although Ratched's main antagonist has been removed, her vocal chords have been severely damaged, and now the patients can think for themselves without her intimidation.
One Flew Over the Cuckoo's Nest refers constantly to different authorities that control individuals through subtle and coercive methods. The novel's narrator, the Chief, combines these authorities in his mind, terming them "The Combine" in reference to the mechanistic way they manipulate and process individuals. The authority of The Combine is most often personified in the character of Nurse Ratched who controls the inhabitants of the novel's mental ward through a combination of rewards and subtle shame. Although she does not normally resort to conventionally harsh discipline, her actions are portrayed as more insidious than those of a conventional prison administrator. This is because the subtlety of her actions prevents her prisoners from understanding that they are being controlled at all. The Chief also sees the combine in the damming of the wild Columbia River at Celilo Falls, where his Native American ancestors hunted, and in the broader conformity of post-war American consumer society. The novel's critique of the mental ward as an instrument of oppression comparable to the prison mirrored many of the claims that French intellectual Michel Foucault was making at the same time. Similarly, Foucault argued that invisible forms of discipline oppressed individuals on a broad societal scale, encouraging them to censor aspects of themselves and their actions. The novel also subtly critiques the emasculation of men in society particularly in the character of Billy Bibbit, the stuttering acute who is domineered by both Nurse Ratched and his mother.
Chief Bromden: The novel's Native American narrator, the Chief has been in the mental hospital since the end of World War II. Bromden pretends to be deaf and dumb, and he is privy to many of the ward's dirty secrets.
As a young man, the Chief was a high school football star, a college student, and a war hero. After seeing his father, a true Indian chief, humiliated at the hands of the government and his white wife, Chief falls into schizophrenia. He believes society is controlled by a large, malignant system which he calls "The Combine".
The Chief sees people as they are, not as they appear. While he is a very strong man of over six-and-a-half feet tall, he sees himself as a small man, and strong-spirited people such as McMurphy and Ratched as large. It is only when McMurphy helps him regain his self-respect that he finally stops hallucinating.
Randle McMurphy: A rebellious convict sent from a normal prison. He is guilty of battery and gambling (he had also been charged with, but never convicted of, statutory rape). McMurphy is transferred from a prison work farm to the hospital, thinking it will be an easy way to serve out his sentence in comfort. He has a fine time hustling the patients, until he realizes that he is more than a diversion for them: he gives them the lives they are too afraid to live for themselves. In himself he discovers devotion to his friends and the capacity for self-sacrifice. In the end, McMurphy violently fights Nurse Ratched's rule which costs him his freedom, his health and, ultimately, his life.
The "Black Boys" Washington, Williams and Warren: Three black men who work as aides in the ward. Williams is a dwarf, his growth stunted after witnessing his mother's rape by white men. The Chief says Nurse Ratched hired them for their sadistic nature. They are cruel and vindictive men who are unable to dominate McMurphy. It is also implied several times that they both beat and rape patients.
Dr. Spivey: The spineless ward doctor. While Nurse Ratched managed to drive off all the other doctors, she kept Spivey because he always did as he was told. Harding suggests that the nurse may threaten to expose him as a drug addict, though whether he really is an addict is unknown. McMurphy's rebellion inspires him to stand up to Nurse Ratched by presenting some fresh ideas.
Nurse Pilbow: The young night nurse. Her face, neck and chest are stained with a profound birthmark. She is intensely Catholic and presents symptoms of Peccatophobia (fear of sinning or imaginary crimes). According to the Chief, she spends her time off either praying for the birthmark to disappear or scrubbing it furiously until her skin bleeds. She blames the patients for infecting her with their evil and takes it out on them.
The Japanese Nurse: A tiny woman, she runs the upstairs ward, which is reserved for violent or otherwise unmanageable patients. She treats her patients kindly and openly opposes Nurse Ratched's methods.
The PR man: A strange individual who is responsible for the hospital's public relations. The patients suspect he wears a corset, and sometimes he laughs hysterically when there are no other staff around.
Geever: A night aide. He is the one who discovers that the Chief is hiding old wads of gum under his bed.
Mr. Turkle: An elderly African American aide who works the late shift in the ward. The Chief notes that Turkle is far more kindly than the other aides. He agrees to allow McMurphy to host a party and sneak in prostitutes one night. He is a marijuana user, and shares his joint with some of the patients during the party.
Billy Bibbit: A nervous, shy, and boyish patient with an extreme speech impediment. Billy cuts himself and has attempted suicide numerous times. Nurse Ratched is a close friend of Billy's overbearing mother, who treats him like a child, despite his being in his thirties. To alleviate Billy's fear of women, McMurphy sneaks a prostitute into the ward so Billy can lose his virginity. Upon being discovered the next morning, Billy speaks for the first time without stuttering. It is only after Nurse Ratched threatens to tell his mother that Billy reverts back to his nervous ways. Fearing the loss of his mother's love after hearing Ratched's threat, Billy has an emotional breakdown and cuts his own throat.
Dale Harding: The unofficial leader of the patients before McMurphy arrives. Harding is an intelligent, good-looking man who is ashamed of his femininity. Harding's beautiful yet malcontented wife is a source of shame for him; he cannot pleasure her, thus constanstly emasculating him.
George Sorensen: A man with germaphobia. He spends his days washing his hands in the ward's drinking fountain. McMurphy manages to convince him to lead a fishing expedition for the patients. Afterwards, the staff forcibly delouse him, conscious of the mental anguish that they are causing him. The delousing is a retribution by Nurse Ratched, rather than medical care. McMurphy and the Chief stop the delousing and, because of their actions, end up in the disturbed ward.
Charles Cheswick: A loudmouthed patient always demanding change in the ward, but who never has the courage to see anything through. According to Ratched he "climbs onto a soapbox" and "shouts for a following" but backs down when there are any repercussions by the Big Nurse from his demands. He finds a friend in McMurphy, who is able to voice his opinions for him. After McMurphy loses his confidence when he learns that his stay in the ward is indefinite, Cheswick drowns himself in the swimming pool.
Martini: A patient who suffers from severe hallucinations. He frightens McMurphy by talking about the people who "need [McMurphy] to see them", that is, the people who need McMurphy to stand up for them.
Scanlon: A patient obsessed with explosives and destruction. Aside from McMurphy and Bromden, he is the only non-vegetative patient there by force, the rest could leave at anytime. It is Scanlon who convinces the Chief to escape.
Sefelt and Fredrickson: Two epileptic patients. Jim Sefelt refuses to take his anti-seizure medication, as it makes his hair and teeth fall out. He is plagued by seizures, which the Chief believes are controlled by Nurse Ratched. Bruce Fredrickson takes Sefelt's share of the medication, because he is terrified of the seizures.
Max Taber: An unruly patient who was released before McMurphy arrived. The Chief recalls how, after questioning what was in his medication, Nurse Ratched had him 'fixed.' He walked out of the hospital a sane man, a tribute to the Combine's terrible power. It is suggested that he was raped by the "Black Boys"
Chief Bromden (See above)
Ruckly: A hell-raising patient who challenges the rules until his lobotomy. After the lobotomy, he sits and stares at a picture of his wife, and occasionally screams profanities. He is kept in the ward as a reminder of what happens to patients who get out of line.
Ellis: Ellis was put in a vegetative state by electroshock therapy. He stands against the wall in a disturbing Christ-like position with arms outstretched, day after day, as if he were nailed there.
Pete Bancini: Bancini suffered brain damage at birth, but managed to hold down simple jobs until he was institutionalized. He sits, wagging his head and complaining how tired he is. The Chief remembers how once, and only once, he lashed out violently against the aides, telling the other patients that he was a living miscarriage, born dead.
Rawler: A patient on the disturbed ward, he says nothing but "loo, loo, loo!" all day and tries to run up the walls. The Chief believes he has been wired to receive radio transmissions. One night, Rawler castrates himself while sitting on the toilet and bleeds to death before anyone realizes what he has done.
Old Blastic: An old patient who is in a vegetative state. The first night McMurphy is in the ward, Bromden dreams Blastic is hung by his heel and sliced open, spilling out his rusty guts. The next morning it is revealed that Blastic died during the night.
The Lifeguard: An ex-professional football player, he still has the cleat marks on his forehead from the injury that scrambled his brains. While he is the lifeguard at the hospital pool, he remains in the disturbed ward because he occasionally tackles the nurses. This is fine with him, because he doesn't realize he's in a mental hospital. It is the lifeguard who tells McMurphy that he will stay in the hospital until Nurse Ratched decides he may go, regardless of his original prison sentence.
Colonel Matterson: The oldest patient in the ward, he suffers from severe senile dementia and cannot move without a wheelchair. He is a veteran of the First World War, and spends his days "explaining" objects ("Mexico...is a walnut."). The Chief believes there is logic to his babbling.
Sandy: Another prostitute and friend of McMurphy, she shows up with Candy on the night of the party. She and Sefelt sleep together (Sefelt has a seizure while they are having sexual intercourse, giving Sandy an experience she'll never forget).
Vera Harding: Dale Harding's beautiful wife, who visits him faithfully but flirts with the other men while she's there. Harding mocks her lack of education and refinement; she mocks Harding's lack of manhood.