You need to know the probability of intelligent life evolving on a planet of the red sun Betelgeuse. But first you need to know how to pronounce Betelgeuse. Who you gonna call? Asimov, of course, the only contemporary author who measures his output in astronomical units. He has been writing a popular science column for The Magazine of Fantasy and Science Fiction for over 25 years; this volume reprints columns from 1983-84. Asimov is now Lewis Thomas and--these are not quiet, meditative syntheses of science and philosophy, body and spirit and mind. Asimov is a crass though often engaging wholesaler of facts--in such weak entries here as his essay on the moons of the solar system, those facts are simply laid out--like the moons--in a line from here to Pluto. Elsewhere, however, the expository skills of a fine teacher are clearly evident, as in the essay on photosynthesis, a tour de force of lucid explanation and casual learnedness. The physics section is occasionally hard to track, but is mercifully free of those irritating analogies ("If the Universe were a football field and Earth was in the end zone. . .") that make "popular" science so widely and deservedly unpopular. Asimov is crystal clear on the slippery topic of general relativity and recent efforts to prove it experimentally. (Surprisingly, the first strong proof did not emerge until five years after Einstein's death.) This is a highly formulaic writer, of course, but the formula here--a brief anecdote followed by a related essay on some topic from applied or theoretical science--often yields an informative piece, particularly when the topic is biology, chemistry, or the history of science. Asimov says he enjoys this column more than any of his other regular writing assignments. In many of these essays, the pleasure shines through.