I read on the cover of this book that David Brin has won the Hugo and Nebula awards, and that he's known for "rich characterisation" and "state-of-the-art science". He's a Real Scientist working on space science at the University of California (San Diego). I thought I ought to give him a try; but I wasn't expecting light reading.
However, light reading was exactly what I got. It turns out to be a pleasant and amusing frolic. The central idea is novel and delightful; it's developed quite straightforwardly and competently, but neither the characterisation nor the scientific content are really anything to write home about. The Practice Effect itself seems so implausible in scientific terms that I'm tempted to class the book as fantasy. But I've no objection to fantasy, in moderation; and I do vaguely remember hearing about some far-out modern scientific theory that may have inspired this flight of fancy.
The book comes to a fairly definite end which doesn't encourage speculation about sequels. Most sf authors, having come up with a novel idea, would determinedly set out to milk it of every drop of fictional possibility. Brin evidently reckons there are more ideas where that one came from. Well, I'll try his other books and see.
Originally published in Thurb 13 in March 1986
Fast forward to October 2006... I did try several of his other books, and quite liked them. But The practice effect remains my favourite, and I reread it from time to time. His later books are more serious and heavy, and I read fiction above all for entertainment.