Roger Zelazny is a frustrating writer. He is capable of startlingly original writing, powerful scenes and new ideas in a field where ideas tend to be a bit threadbare from overuse. And yet, about halfway through his latest novel, Roadmarks …, he seems to get bored and throws his book away. The ideas are potentially very good: a freeway through time, where new exits and new forks in the road are created whenever travelers make some change in history and where old roads fade away as they are left unused: the son of one of these time travelers, who searches up and down the road for the father who abandoned him in—of all places—Cleveland; a man who suspects he is immortal and keeps having fits of madness in which he dreams of earlier lives and earlier memories; a character obsessed with altering the past so that this...