The third installment in the Time's Tapestry series features serviceable prose, but some of the unrealized futures that are shown seem highly dubious and like heavy-handed allegories for modern paranoias. Other developments appear to reflect Baxter's frustration with current space programs. The characters are unlovable but determined.
Finally, the struggle becomes about determining in which direction Columbus will set out, either to the history we know or to a dystopia. (Ace, Jan., 336 pp., $24.95)