Believe it or not, this 55-piece collection of writings on sf is a first for the prolific, erratic, unself-critical Asimov. Most of the items are from the late 1970s (the two 1962 introductions to volumes of Soviet sf are painfully out-of-date); they include 22 editorials from his Science Fiction Magazine, pieces from Newsday, from encyclopedias, sf fanzines, TV Guide, Natural History (as well as three not previously published); the content is correspondingly varied and variable. In the first section, "SF in General," Asimov takes five stabs at defining sf (the same examples crop up) and still comes up empty-handed ("surely not all sf can be viewed as travel tales"); "The Predictions of SF" contains one essay with some bite (how sf can foresee and help solve problems), and a second that's no more than a list of future possibilities. "The Writing of SF" is all editorials--mostly routine exhortations to budding writers ("under no circumstances should you describe Titan as a satellite of Jupiter"); "SF Fans"--editorials too--might be of some interest to Trekkies and other perennial convention-goers. "The History of SF" has its anecdotes, as does "SF Writers"--on Campbell and his wife Peg, H. L. Gold, Gernsback, Weinbaum. There's also a blurb-style discussion of Bradbury, and a mention of Asimov's mutual-admiration society with Arthur Clarke. "SF Reviews" features Asimov's only serious attempt at criticism: he tackles 1984 from an sf point of view (but why assume it's sf? Orwell didn't) and comes disastrously unstuck. On firmer ground, he gleefully chews up and spits out "Battlestar Galactica" and other "Star Wars" imitations; and wheels out Byron, Coleridge, and Sterne to attack critics in general. Bringing up the rear, "SF and I" more or less describes itself. What it all adds up to is hard to say: cognoscenti will find it repetitive, shallow, and banal; intelligent general readers will be repelled by Asimov's opinionated verbosity and facile attempts at humor. But dutiful disciples of the Master will at least give it a once-over.