Carr has assembled twelve stories from the early Forties, most of them perennially available in other collections: old favorites like Henry Kuttner's ""The Twonky,"" Heinlein's ""By His Bootstraps,"" del Rey's ""The Smallest God,"" and Asimov's ""Nightfall."" But, widely anthologized though they may be, Carr lights them up with a degree of critical and historical acumen rarely to be found in histories of science fiction, much less anthologies. His introductions are perspicuously organized, lengthily documented critical essays incorporating a wealth of new and old material. Without condescension or romanticizing, Carr manages to convey the contexts within which these stories were originally written and read. Efficiently sorting out the reigning favorites, newer writers, and influential editors of the day, he presents an uncommonly lucid picture of the Forties science-fiction market in terms of the various magazines and their readerships. Invaluable.