An agreeably low-key survey of investment opportunities in precious and so-called strategic metals from a markets expert (with Canada's Guardian Trust) who eschews all-out recommendations. Cavelti devotes about equal attention to gold, silver, platinum group metals, and the 20-odd non-fuel minerals--cobalt, beryllium, germanium, manganese, tungsten--whose iffy availability from Third World or socialist-bloc sources could have military implications for the West. In each case, he provides a concise review of the metal's history, applications, and supply-demand prospects. (If all the world's gold mines were closed, for instance, industry could make do with above-ground stocks; but any cutback in the production of platinum--vital in catalytic technology, and diverse manufactures--would cause severe disruptions.) Besides weighing the price outlook in this sort of perspective, Cavelti also examines the pros and cons of taking investment positions via bullion, coinage, futures contracts, certificates of ownership, mutual funds, managed accounts, warehouse receipts, and/or the common stock of mining companies; almost never, he stresses, should such holdings exceed 10 percent of an individual's portfolio. Charts and tables track long-term price trends, summarize various material groups, and otherwise impose order on a diffuse subject. A smart, balanced introduction--even for market-wise pros.