From the author of The Wasp Factory and Walking on Glass: a voluminous, sometimes exciting space-opera where character motivations are the most troubling of several knotty problems. Two far-future galactic empires are at war: the Earth-derived Culture, tolerant, unwarlike, vaguely communistic, is ruled by Minds, artificial intelligences of imponderable power and scope; the Idirans, bulky, three-legged alien conquerors who have made warfare into a religion, are implacably opposed to the Minds. Horza, a genetically engineered human with shape-shifting abilities, sides with the Idirans because he prefers biologicals to machines. His mission--numerous adventures intervene--is to capture a disabled Mind that has taken refuge in some ancient tunnels on a Planet of the Dead. In pursuing the Mind, Horza finds himself fighting the same Idirans who are supposed to be his allies. The mechanics of all this haven't been thought through--Horza's adventures, for instance (actually short stories tacked on), eclipse his supposedly supremely important mission. Neither does his decision to fight for the brutal, fanatical Idirans against the vastly more civilized and appealing Culture add up. And we never learn what the Minds do, or what the Idiran religion consists of. Overextended and jarring, then, but imaginative and gripping in places.