Moskowitz is known among sf buffs for some of the most useful historical surveys of the field (Explorers of the Infinite, 1963; Seekers of Tomorrow, 1967). A lapidary stylist he's not, but his indefatigable pursuit of names, dates, and publishing data deserves the gratitude of thousands. Here he takes the rather hazy topic of sf as predictor of important social or attitudinal changes (as opposed to technological innovations). Don't expect much in the way of challenging thesis, despite a blurb to the contrary. Moskowitz does what he's best at: runthroughs of neatly grouped historical examples, mostly from the late 19th century and the great pulp wars. Among the subjects: sf depictions of religious themes, Jews and Negroes, Amazon societies, psychiatric motifs, future wars. There are intriguing chapters on teen sf from the first Tom Swifts to Heinlein's delightful juveniles; Charles Fort the purveyor of ""unexplained phenomena"" and anti-scientific diatribes; Virgil Finlay the celebrated pulp illustrator. Occasionally Moskowitz rises to a bit of direct evaluation (""At no point in the past was science fiction in advance of the times in depicting the Negro""), but in general this is more valuable as a reference aid than as a spark-striking analysis.