Postman has swung dogmatically from Teaching as a Subversive Activity (1969) to Teaching as a Conserving Activity (1979) and landed, now, in the coils of social history. His simple, endlessly elaborated theme: ""the symbolic area in which a society conducts itself will either make childhood necessary or irrelevant."" This translates into the notion of childhood being ""invented"" along with the printing press--since only adults would be privy to the secrets locked into the printed word--and childhood disappearing with the advent of electric communication, to which everyone has access. Postman sees shame as another, implicated requirement for the existence of childhood. In the Middle Ages, there were no secrets from young people; with the advent of literacy, came a ""civilizing process."" Indeed, ""Erasmus was the Judy Blume of his day,"" though his intention was not to reduce a sense of shame but to increase it. (That most adults were no more literate than an unschooled child is only one vital factor that does not enter into this scheme.) The book's second half is largely composed of inflated commonplaces about television: it ""expresses most of its content in visual images, not language""; the news is homogenized and trivialized; children are ""adultified"" and adults are ""childified"" (they don't take their work seriously, have no politics, make no serious plans, etc.). Postman also deplores the sex and violence, illness and marital discord, that an eight-year-old can now see; though it may be ""hypocrisy to hide from children the 'facts' of adult violence and moral ineptitude, it is nonetheless wise to do so."" (What changes to bring about, and how, he doesn't say.) Anyone seriously interested in the problem of today's truncated childhood should get hold of David Elkind's Hurried Child (1982). This is shaky theorizing and crude polemics with a topical hook.