A big, ambitious, highly imaginative but less than fully persuasive novel from the author of Blood Music (p. 62). In the near future, after a limited nuclear war, a large asteroid--the "Stone"--takes up orbit around the Earth. The Stone is hollow, containing six huge, apparently abandoned chambers, cities, lights, forests, and whatnot--and a mind-boggling seventh chamber, a corridor that somehow continues beyond the exterior length of the Stone! As the Western allies explore the Stone (the Russians are mostly excluded), they find books detailing the Stone's past (it was built in an alternate universe) and future (a full-scale nuclear war is about to happen). Then a Russian invasion of the Stone duly triggers the war on Earth; so the surviving invaders and occupants alike are marooned in the Stone--where they're being observed by ghostlike beings from the mysterious corridor. Thereafter, things get complicated. The corridor, or "Way," extends indefinitely in time as well as space; along its length are openings, "Gates," into other worlds. Far down the Way, Axis City is the hub of a large inter-Gate trading complex--but it's threatened with invasion by the enigmatic, hostile Jarts. The humans in the Stone, led by administrator Garry Lanier and mathematics whiz Patricia Vasquez, become integral to the Axis City political disputes stirred up by agent Olmy: one faction favors accelerating the City along the Way to shut out the Jarts; others agitate for a return down the Way to help out their hapless ancestors on the devastated Earth. An impressive and often absorbing enterprise, but patchy and problematic, from the unconvincing characters and poor descriptions to fizzling subplots and the prolonged, dull opening. And even when the narrative finally gathers momentum and excitement, the many dazzling ideas here are never firmly under control.