11. Last and First Men - Olaf Stapledon

One of the most extraordinary, imaginative and ambitious novels of the century: a history of the evolution of humankind over the next 2 billion years. Among all science fiction writers Olaf Stapledon stands alone for the sheer scope and ambition of his work. First published in 1930, Last and First Men is full of pioneering speculations about evolution, terraforming, genetic engineering and many other subjects.

12. Earth Abides - George R. Stewart

In this profound ecological fable, a mysterious plague has destroyed the vast majority of the human race. Isherwood Williams, one of the few survivors, returns from a wilderness field trip to discover that civilization has vanished during his absence. Eventually he returns to San Francisco and encounters a female survivor who becomes his wife. Around them and their children a small community develops, living like their pioneer ancestors, but rebuilding civilization is beyond their resources, and gradually they return to a simpler way of life.

13. Martian Time-Slip - Philip K. Dick

Mars is a desolate world. Largely forgotten by Earth, the planet remains helpless in the stranglehold of Arnie Kott, who as boss of the plumber's union has a monopoly over the vital water supply. Arnie Kott is obsessed by the past; the native Bleekmen, poverty-stricken wanderers, can see into the future; while to Manfred, an autistic boy, time apparently stops. When one of the colonists, Norbert Steiner, commits suicide, the repercussions are startling and bizarre.

Another of Dick's superb views of the future, creating an initially bizarre world, which slowly begins to make sense as the plot unfolds.

14. The Demolished Man - Alfred Bester

In the year 2301, guns are only museum pieces and benign telepaths sweep the minds of the populace to detect crimes before they happen. In 2301 murder is virtually impossible, but one man is about to change that... Ben Reich, a psychopathic business magnate, has devised the ultimate scheme to eliminate the competition and destroy the order of his society. The Demolished Man is a masterpiece of imaginative suspense, set in a superbly imagined world in which everything has changed except the ancient instinct for murder.

Another excellent piece of writing by Bester. Every bit as fast-paced and compelling as 'The Stars My Destination' and a fascinating read.

15. Stand On Zanzibar - John Brunner

There are seven billion-plus humans crowding the surface of 21st century Earth. It is an age of intelligent computers, mass-market psychedelic drugs, politics conducted by assassination, scientists who burn incense to appease volcanoes ... all the hysteria of a dangerously overcrowded world, portrayed in a dazzlingly inventive style. Employing a dazzling range of literary techniques, John Brunner has created a future world as real as this morning's newspaper - moving, sensory, impressionistic, as jagged as the times it portrays, this book is a real mind stretcher - and yet beautifully orchestrated to give a vivid picture of the whole.

A superb piece of writing by Brunner, which is made all the more compelling and fascinating by the mixture of styles the book employs.

16. The Dispossessed - Ursula Le Guin

The Principle of Simultaneity is a scientific breakthrough which will revolutionize interstellar civilization by making possible instantaneous communication. It is the life work of Shevek, a brilliant physicist from the arid anarchist world of Anarres. But Shevek's work is being stifled by jealous colleagues, so he travels to Anarres's sister-planet Urras, hoping to find more liberty and tolerance there. But he soon finds himself being used as a pawn in a deadly political game.

A popular favourite book among scientists (and Ken Livingstone!).

17. The Drowned World - J. G. Ballard

In the 21st century, fluctuations in solar radiation have caused the ice-caps to melt and the seas to rise. Global temperatures have climbed, and civilization has retreated to the Arctic and Antarctic circles. London is a city now inundated by a primeval swamp, to which an expedition travels to record the flora and fauna of this new Triassic Age. This early novel by the author of 'Crash' and 'Empire of the Sun' is at once a fast paced narrative, a stunning evocation of a flooded, tropical London of the near future and a speculative foray into the workings of the unconscious mind.

18. The Sirens Of Titan - Kurt Vonnegut

Winston has flown his craft into a chrono-synclastic infundibulum, and been converted into pure energy. Materializing only when his waveforms intercept a planet, he only gets home once every 59 days. But at least it's some consolation that he knows all that ever has been and all that ever will be.

A supremely funny, and well-observed novel by Vonnegut, mixing up some superb ideas with an intriguing and ultimately rewarding story.

19. Emphyrio - Jack Vance

Far in the future, the craftsmen of the distant planet Halma create goods which are the wonder of the galaxy. But they know little of this. Their society is harshly regimented, its religion austere and unforgiving, and primitive -- to maintain standards, even the most basic use of automation is punishable by death. When Amiante, a wood-carver, is executed for processing old documents with a camera, his son Ghyl rebels, and decides to bring down the system. To do so, he must first interpret the story of Emphyrio, an ancient hero of Halman legend.

20. A Scanner Darkly - Philip K. Dick

Substance D -- otherwise known as Death -- is the most dangerous drug ever to find its way on to the black market. It destroys the links between the brain's two hemispheres, leading first to disorentation and then to complete and irreversible brain damage. Bob Arctor, undercover narcotics agent, is trying to find a lead to the source of supply, but to pass as an addict he must become a user, and soon, without knowing what is happening to him, he is as dependent as any of the addicts he is monitoring.