In this wide-ranging series of essays, an award-winning science fiction critic explores how the related genres of science fiction, fantasy, and horror evolve, merge, and finally evaporate into new and more dynamic forms. Beginning with a discussion of how literary readers unlearned how to read the fantastic during the heyday of realistic fiction, Gary K. Wolfe goes on to show how the fantastic reasserted itself in popular genre literature, and how these genres themselves grew increasingly unstable in terms of both narrative form and the worlds they portray. More detailed discussions of how specific contemporary writers have promoted this evolution are followed by a final essay