 Science fiction, at its best, makes us question what we understand and doubt the world we live in. Even so, few works are as unsettling as The Islanders by Christopher Priest (Gollancz, ?12.99). This drily comic gazetteer of the Dream archipelago hides stories of horror, artistic rivalry and possibly murder. But even as you disentangle these stories, revealed piecemeal, out of chronological order, and from different viewpoints, other puzzles keep arising. There are no simple answers, but the endless questions make this one of the most complex, challenging and satisfying fictions from one of our finest novelists.  There are more puzzles in Osama by Lavie Tidhar (PS, ?19.99), in which a detective roams a noirish landscape in search of the author of a series of pulp novels about Osama bin Laden: Vigilante. It is a world in which bin Laden's terrorist atrocities never happened, but which is none the less haunted by them. Nina allan's The Silver Wind (Eibonvale, ?18) also takes us into an alternate world, a dystopian England being the setting for one of the linked stories that make up this subtle and disturbing meditation on time.  Wind angels (PS, ?19.99) is a long-awaited collection of stories from Leigh Kennedy, shifting deftly from sci-fi to fantasy to mainstream. The title story, about an England submerging after climate change, shows how skilled a writer she is.  More stories in Manhattan in Reverse (Macmillan, ?17.99), a rare collection from one of sci-fi's more engaging storytellers, Peter F Hamilton. Like Tidhar and Priest, he uses crime as a way to open up profoundly different worlds, including two tales from his bestselling Commonwealth series.  PaUL KINCaID