Originating as a BBC radio series in 1978, Douglas Adams's inspired melding of hippy-trail guidebook and sci-fi comedy turned its novelisations into a publishing phenomenon. Douglas wrote five parts from 1979 onwards (the first sold 250,000 in three months), introducing the world to Marvin the Paranoid Android, the computer Deep Thought, space guitarist Hotblack Desiato (named after Adams's local estate agent) and the Guide itself, a remarkably prescient forerunner to the internet. Aldiss's first novel is a tour-de-force of adventure, wonder and conceptual breakthrough. Set aboard a vast generation starship millennia after blast-off, the novel follows Roy Complain on a voyage of discovery from ignorance of his surroundings to some understanding of his small place in the universe. Complain is spiteful and small-minded but grows in humanity as his trek through the ship brings him into contact with giant humans, mutated rats and, ultimately, a wondrous view of space beyond the ship. One of the first attempts to write a comprehensive "future history", the trilogy - which also includes Foundation and Empire (1952) and Second Foundation (1953) - is Asimov's version of Gibbon's Decline and Fall of the Roman Empire, set on a galactic scale. Hari Seldon invents the science of psychohistory with which to combat the fall into barbarianism of the Human Empire, and sets up the Foundation to foster art, science and technology.

When Haldeman returned from Vietnam, with a Purple Heart for the wounds he had suffered, he wrote a story about a pointless conflict that seems as if it will never end. It was set in space, and the enemies were aliens, but 18 publishers decided it was too close to home before St Martin's Press took a gamble. The book that "nobody wants to read" went on to win many prizes. It's not perfect - it's hard to take seriously a future in which hetereosexuality is a perversion - but the anti-war message is as powerful as ever. Known for his intricate short stories and critically acclaimed mountaineering novel Climbers, Harrison cut his teeth on SF. In typical fashion, he writes space opera better than many who write only in the genre. For all its star travel and alien artefacts, scuzzy 25th-century spaceports and drop-out space pilots, Light is actually about twisting three plotlines as near as possible to snapping point. This is as close as SF gets to literary fiction, and literary fiction gets to SF. Jon Courtenay Grimwood Buy this book at the Guardian bookshop Amateur stonemason, waterbed designer, reformed socialist, nudist, militarist and McCarthyite, Heinlein is one of the most interesting and irritating figures in American science fiction.