41. Jem - Frederik Pohl

The discovery of another habitable world might spell salvation to the three bitterly competing power blocs of the resource-starved 21st century; but when their representatives arrive on Jem, with its multiple intelligent species, they discover instead the perfect situation into which to export their rivalries. Subtitled, with savage irony, 'The Making of a Utopia', Jem is one of Frederik Pohl's most powerful novels.

42. Bring The Jubilee - Ward Moore

Trapped in 1877, a historian writes an account of an alternate history of America in which the South won the Civil War. Living in this alternate timeline, he was determined to change events at Gettysburg. When he's offered the chance to return to that fateful turning point his actions change history as he knows it, leaving him in an all too familiar past.

43. Valis - Philip K. Dick

It began with a blinding light, a divine revelation from a mysterious intelligence that called itself VALIS. And with that, the fabric of reality was ripped open and laid bare so that anything seemed possible, but nothing seemed quite right. Part science fiction, part theological detective story - in which God plays both the missing person and the perpetrator of the ultimate crime, VALIS is both disorienting and eerily funny, and a joy to read.

44. The Lathe Of Heaven - Ursula Le Guin

George Orr is a mild and unremarkable man who finds the world a less than pleasant place to live: seven billion people jostle for living space and food. But George dreams dreams which do in fact change reality - and he has no means of controlling this extraordinary power. Psychiatrist Dr William Haber offers to help. At first sceptical of George's powers, he comes to astonished belief. When he allows ambition to get the better of ethics, George finds himself caught up in a situation of alarming peril.

45. The Complete Roderick - John Sladek

Roderick is a robot and this is his autobiography. Sladek conveys, with great sensitivity and insight the innocence of an artificial intelligence and asks profound questions about mankind's right to manipulate others. It also portrays how a numerological mind might structure a narrative. Inventive, funny yet melancholy this is one of SF's greatest creative geniuses writing at his thought-provoking best.

46. Flow My Tears, the Policeman Said - Philip K. Dick

Jason Taverner is a Six, the result of top secret government experiments forty years before which produced a handful of unnaturally bright and beautiful people - and he's the prime-time idol of millions until, inexplicably, all record of him is wiped from the data banks of Earth. Suddenly he's a nobody in a police state where nobody is allowed to be a nobody. Will he ever be rich and famous again? Was he, in fact, ever rich and famous?

47. The Invisible Man - H. G. Wells

Griffin is a brilliant and obsessed scientist who is dedicated to achieving invisibility. He takes whatever action is necessary to keep his incredible discovery safe and terrorises the local village where he has sought refuge. Gradually he loses his sanity and, ultimately, his humanity.

Despite its somewhat antiquated prose, 'The Invisible Man' is still a well-written piece of science-fiction, and a true classic.