One Flew Over the Cuckoo’s Nest [suggested by Ross Allatt]

An international bestseller, Ken Kesey’s One Flew Over the Cuckoo’s Nest defined the 1960s era of ever-widening perspectives and ominous repressive forces. Full of mischief, insight, and pathos, Kesey’s powerful story of a mental ward and its inhabitants probes the meaning of madness, often turning conventional notions of sanity and insanity on their heads.
The tale is chronicled by the seemingly mute Indian patient, Chief Bromden; its hero is Randle Patrick McMurphy, the boisterous, brawling, fun-loving rebel who encourages gambling, drinking, and sex in the ward, and rallies the other patients around him by challenging the dictatorial rule of Big Nurse. McMurphy’s defiance — which begins as a sport — develops into a grim struggle with the awesome power of the “Combine”, concluding with shattering, tragic results. In its unforgettable portrait of a man teaching the value of self-reliance and laughter destroyed by forces of hatred and fear, One Flew Over the Cuckoo’s Nest is a classic parable that has left an indelible mark on the literature of our time. [Inside cover blurb]
The book has a Wikipedia page and has also been made into a film, which has its own Wikipedia page.
Author’s Wikipedia page.
Shortlisted for this month
The book selector for the month can choose up to three books for nomination. This month Ross’s other choices, all of which have been filmed at least once, were:
Lolita

One of the most controversial novels of the twentieth century, Vladimir Nabokov’s Lolita is a strange, troubling love story told by the one of the most unreliable narrators in literature.
Poet and pervert, Humbert Humbert becomes obsessed by twelve-year-old Lolita and seeks to possess her, first carnally and then artistically, out of love, ‘to fix once for all the perilous magic of nymphets’. Is he in love or insane? A silver-tongued poet or a pervert? A tortured soul or a monster? Or is he all of these? Humbert Humbert’s seduction is one of many dimensions in Nabokov’s dizzying masterpiece, which is suffused with a savage humour and rich, elaborate verbal textures. [product description from Amazon]
The book has a Wikipedia page, and as mentioned above was filmed first by Stanley Kubrick in 1962 starring James Mason and Sue Lyon, and again in 1997 by Adrian Lyne starring Jeremy Irons and Dominique Swain. (Both versions also have Wikipedia entries)
Author’s Wikipedia page.
Author’s biographical notes on the Britannica website.
American Psycho

Brett Easton Ellis established a reputation as the enfant terrible of American fiction in the 1980s with his controversial novel Less than Zero, but with the publication of American Psycho he became established as one of the most notorious and reviled novelists currently writing. American Psycho deserves its controversy. The novel opens with a sign scrawled above a New York subway station: “Abandon hope all ye who enter”. So begins a hellish descent into the world of Patrick Bateman, the novel’s protagonist. Bateman is a handsome 26-year-old Wall Street yuppie, who spends his days listening to Whitney Houston and working out which exclusive restaurant to eat in and what clothes to wear in a dizzying parody of 1980s consumerism run mad.
However, Bateman also has a darker side; he is a psychopathic serial killer, with a penchant for torturing and sexually abusing young women before killing them in the most gruesome and explicit fashion. The novel contains little actual plot, and consists of extended descriptions of exclusive restaurants, designer clothes, TV shows and the minutiae of Bateman’s vacuous world, relieved only by clinically described scenes of torture and mutilation which are not for the faint-hearted. Bateman makes little attempt to justify his actions, merely claiming that “this is the way the world–my world–moves”. As a satire on the bankrupt, money-driven world of the 1980s, American Psycho is a successful, if rather heavy-handed piece of fiction, whose controversy seems only set to increase. –Jerry Brotton [writing on Amazon].
The book has a Wikipedia page and has also been made into a film which has its own Wikipedia page.