I thought it would be good to qualify a list I posted earlier. Too difficult to type on an iphone. Please bear in mind that we are way beyond these numbers now.
276. The Drowned World JG Ballard
277. Vermilion Sands JG Ballard
278. The Status Civilisation Robert Sheckley
279. Cats Cradle Kurt Vonnegut
290. The Sirens of Titan Kurt Vonnegut
291. The Garments of Caen Barrington Bayley
292. An Alien Heat Michael Moorcock
293. The Tripods Trilogy John Christopher
294. Hothouse. Brian Aldiss
So:
Drowned World. JG Ballard. Seminal new-wave inner space SF 1960s British SF. Ecological disaster, with a deeply ambiguous main character. Should be considered alongside Ballard's The Crystal World and The Drought.
Vermilion Sands. JG Ballard. SS collection set in the eponymous faded desert resort, in which equally faded and jaded starlets, poets, architects and hangers-on maintain superficial elegance, manners and artistic pretence, whilst succumbing to ennui. Atmospheric and beguiling, as with all of the best Ballard.
Status Civilization by Robert Sheckley. Absurdist SF. TBH could have picked one from a number of Sheckley novels. He needs to be better remembered.
Cat's Cradle by Kurt Vonnegut. Absurdist SF and religious parody, with the brilliant SF idea of ice-9.
The Sirens of Titan by Kurt Vonnegut. Yet more absurdist SF, this time quite movingly sad in places.
The Garments of Caen J Barrington Bayley. New Wave SF. Wry SF conceit about sentient clothes. Reads a bit like Jack Vance.
An Alien Heat. Michael Moorcock. The first of the Dancers at the End of Time books. Lush unrestrained and psychedelic sf set at the end of the universe, when the last few immortal individuals on Earth possess unlimited power and almost childlike naivety, spending their time making ridiculous artistic installations, having affairs and parties, and generally being decadent.
The Tripods trilogy John Christopher. YA dystopia, where the earth is controlled by aliens who live in domed cities and dominate through WOTW-type tripods. Hugely influential.
Hothouse Brian Aldiss. Far future, Earth dominated by tropical jungle, and the barely recognisable descendants of humanity struggle for existence.