Silberg proposes to put twentieth-century society in evolutionary relation to societies of the past. He focuses on the contrast between reverent, non-alienated ""primitives"" and shallow, anxious, hyper-rational modern man. (Devolution means passage from stage to stage, rolling down, degeneration.) He builds two theories: culture as the result of our social orientation, and ""positive affect"" as the key to individual psychology. The problem of how we got from noble savagery to our present ignoble state is subordinated to the development of these rather fuzzy ""idea systems."" Silberg roasts such already overdone chestnuts as Dostoyevsky and the Absurd, inner- and other-directedness, but scarcely examines the rise of Cultural institutions (schools, press, popular literature, etc.) The sources for his abundant quotes include few of the great writers on culture. He ably summarizes others' views, but relies on metaphor rather than conceptual or historical analysis to make his key points. Students and upper-middlebrows may get something out of them; casual readers and cognoscenti will find the book more portentous than substantive.