The room was quiet; the man in front of the mirror was the only living things there, and he was too horrified to utter a sound. In the mirror, five faces stared back at him: one young and ruddy, which was his own, and four that did not belong in that place at all, for they were wrinkled, malevolent, small as crabapples and blue as smoke. So begins Damon Knight's 'Be My Guest', a story of the human race possessed by things that were - well, not exactly demons . . . but not exactly not demons, either. It's just one of the unpredictably imaginative tales in this fascinating collection by a modern master of science fiction.