Although Brown predicts great sea ""ranches"" worked with the help' of porpoise ""cowboys,"" this actually focuses on the more limited prospects for commercial aquaculture in the near future. . . and on the obstacles that stand in its way, chiefly pollution, but also high costs and our limited knowledge. Brown surveys various research projects and a few established ventures in the U.S. and Japan--artificial reefs; fish farms; the raising of oysters, mussels and shrimp; kelp harvesting. A utilitarian presentation, but straightforward and factual, and the most thorough we've seen.