An old-fashioned anthology of old-fashioned virtues: there's not much in the way of stylistic fireworks or conspicuously labeled profundity here, but rather a clear projection of the relationship between material and treatment that distinguishes the science-fiction form. Asimov's introductory essays sum up what is known to date about the important bodies of our solar system--planets, asteroids, comets--while the twelve stories mostly date from 1955-1965 and embody then-reasonable notions about the same things. Asimov's own "Waterclap" (about competition for funds between a deep-sea project and a lunar colony) is a bit later (1970), but is representative in its efficient writing, economical use of scientific premises, and only slightly qualified optimism about the adventure of space. "Barnacle Bull" by the pseudonymous Winston P. Saunders (Poul Anderson) is a good illustration of Golden Age Jocular at its most pleasant; an early Robert Sheckley story about a Venusian prospector strikes an agreeable note without too many of his usual hijinks; and among deserving contributions by the likes of James Blish, Alexei Panshin, Arthur C. Clarke, and Fritz Leiber, Terry Carr's "Hop-Friend" (in which a friendly Martian turns out to be not quite what he seems) still stands out as one of the most mordant science-fiction stories ever written. An eminently well-designed collection.