Commodities are those ordinary items--coffee, eggs, copper, cocoa, cotton--that have recently become hot properties. Everyone knows what they are worth today, but no one knows what they will be worth in six months. On commodities exchanges, an investor can buy ""futures"" which promise him delivery of the commodity at the price he paid today. The possibilities for gain or loss are apparent--and since the margin requirements for commodities' trading are small and the price fluctuations may be large, big money can be made or lost. The author maintains, however, that knowledge, experience, timing, and good luck will not lead an investor to consistent profits. Most of the book explains why this is so while supplying background on the operations of the commodities markets. In substitution for expertise, Epstein offers a simple, mechanical formula--based upon a seven-week moving average of prices--which involves only the arithmetic skills of addition and division. This instructs the investor whether to buy or sell. Following the formula would have produced good profits over a long period of time--assuming (Epstein warns) an investment of at least $30,000 in a diversified portfolio to allow for the volatility of commodities markets. While mechanical investment is not fun, making money is its own reward; and as long as everyone does not adopt Epstein's system (or any single other), his book is worth the attention of profit-seekers.