21. Star Maker - Olaf Stapledon

One moment a man sits on a suburban hill, gazing curiously at the stars, the next, he is whirling through the firmament, and perhaps the most remarkable of all science fiction journeys has begun.

22. Behold The Man - Michael Moorcock

Meet Karl Glogauer, time traveller and unlikely Messiah. When he finds himself in Palestine in the year 29AD he is shocked to meet the man known as Jesus Christ -- a drooling idiot, hiding in the shadows of the carpenter's shop in Nazareth. But if he is not capable of fulfilling his historical role, then who will take his place?

23. The Book Of Skulls - Robert Silverberg

Four students discover a manuscript, The Book of Skulls, which reveals the existence of a sect, now living in the Arizona desert, whose members can offer immortality to those who can complete its initiation rite. To their surprise, they discover that the sect exists, and is willing to accept them as acolytes. But for each group of four who enter the rite, two must die in order for the others to succeed.

Not one of the greatest novels in the SF Masterworks series, and not really science fiction, 'The Book of Skulls' is nonetheless an interesting read.

24. The Time Machine & The War of the Worlds - H. G. Wells

In 'The Time Machine', Wells's Time Traveller journeys to the world of 802,701 AD, where humanity has divided into the effete, beautiful Eloi and the brutal subterranean Morlocks. In The 'War of the Worlds', the Martians -- intellects 'vast and cool and unsympathetic' -- send their war machines to wreak havoc across the world.

Two of the best-known science-fiction novels ever written, which prove surprisingly accessible even to a modern audience.

25. Flowers For Algernon - Daniel Keyes

Charlie Gordon, IQ 68, is a floor sweeper, and the gentle butt of everyone's jokes, until an experiment in the enhancement of human intelligence turns him into a genius. But then Algernon, the mouse whose triumphal experimental tranformation preceded his, fades and dies, and Charlie has to face the possibility that his salvation was only temporary.

Converted into an Oscar-winning film, 'Charly', 'Flowers For Algernon' is a very well-written and very readable book, taking the form of a series of "progress reports" written by Charlie as he receives the experimental treatment.

26. Ubik - Philip K. Dick

Glen Runciter is dead. Or is he? Someone died in the explosion orchestrated by his business rivals, but even as his funeral is scheduled, his mourning employees are receiving bewildering messages from their boss. And the world around them is warping and regressing in ways which suggest that their own time is running out. If it hasn't already.

Another excellent piece of work by master writer Dick, 'Ubik' creates a bizarre and confusing world, which leaves the reader guessing (and confused!) right up to the end.

27. Timescape - Gregory Benford

1962: A young Californian scientist finds his experiments spoiled by mysterious interference. Gradually his suspicions lead him to a shattering truth: scientists from the end of the century are using subatomic particles to send a message into the past, in the hope that history can be changed and a world-threatening catastrophe averted.

Not one of the best books in the SF Masterworks series, but by no means awful. This is a brilliant idea, but the writing is uneven, and the ultimate conclusion is a little disappointing.

28. More Than Human - Theodore Sturgeon

All alone: an idiot boy, a runaway girl, a severely retarded baby and twin girls with a vocabulary of two words between them. Yet, once they are mysteriously drawn together, this collection of misfits becomes something very, very different from the rest of humanity.

Not one of my favourites from the SF Masterworks, but still very well written, with an interesting story.

29. Man Plus - Frederik Pohl

Ill luck made Roger Torraway the subject of the Man Plus Programe, but it was deliberate biological engineering which turned him into a monster -- a machine perfectly adapted to survive on Mars. For according to computer predictions, Mars is humankind's only alternative to extinction. But beneath his monstrous exterior, Torraway still carries a man's capacity for suffering.

Hmm... 'Robocop' anyone?

30. A Case of Conscience - James Blish

Father Ramon Ruiz-Sanchez S.J., is a part of a four man scientific commission to the planet Lithia, there to study a harmonious society of aliens living on a planets which is a biologist's paradise. He soon finds himself troubled: how can these perfect beings, living in an apparent Eden, have no conception of sin or God? If such a sinless Eden has been created apart from God, then who is responsible?