'Not just good, but fun, capacious, and in parts brilliant' GUARDIAN 'Enjoyable, thought-provoking stuff, with the balls to pursue its speculations to mind-boggling extremes' TIME OUT 'Two titans of hard SF team up for a story of grand scientific and philosophical scope... The large-scale implications addressed are impressive in this potent story' PUBLISHERS WEEKLY 'A sweeping, mind-boggling read' BOOKLIST