As surveys of the genre go, this is bland, efficient, and utterly unchallenging. In fact, it resembles nothing so much as one of those term-paper quarries conveniently pegged at incurious students. At the paperback price it is certainly a bargain of sorts, providing a handy capsule history of sf, an introduction to some scientific assumptions of the form, a guide to some common modes and themes, and brief summaries of ten representative sf novels. Scholes and Rabkin are sensible, middle-of-the-road critics, not without some sharply personal opinions--see, for example, their well-justified annoyance with the later Heinlein. But most of their reactions are packaged in neat little wrap-ups, accurate enough as fax as they go but distinctly unadventurous. The search for easy critical labels tells us that Moorcock's End of Time trilogy is ""wildly escapist"" and unmarred by ""social consciousness"" or that the departure of the children in Clarke's Childhood's End presents a latter-day entry into the kingdom of heaven, a ""monument to man's continual spiritual yearning."" And although there are bound to be some lacunae in any brief survey, it is surprising to find so little of Pohl's or Sheckley's work even mentioned and hard to justify the exclusion of Algis Budrys, Poul Anderson, and Kate Wilhelm. As historians, Scholes and Rabkin are a lot less provocative than Brian Aldiss (Billion Year Spree, 1973). As critics, they are a lot less penetrating than Damon Knight (In Search of Wonder, rev. ed. 1967). Their brief contribution is acceptable as an elementary introduction, disappointing in terms of any larger perspective.