What is referred to in the title? Mr. Lens doesn't beat about the bush. The Futile Crusade is nothing less than ""Anti-Communism as American Policy."" It is a charge which has been made before, but seldom so thoroughly. The strategy we have followed since 1946 is unrealistic, he contends, and ""even if it succeeded it could not possibly keep the United States strong or preserve it as a first-class power. He finds ""its role is negative,"" and it depends ""primarily on military power"" because as in the past, while social power has become the determinant of world affairs."" We must realize, he insists, that Communism is here to stay, and that, as a chapter title indicates, ""Anti-Communism Hardens Communism."" Step by step, from 1917 onward, Mr. Lens reviews the facts, and his considered opinion is that ""our only hope is to co-exist and compete"" with the Soviet's on the social plane, rather than the military level. This means assisting the underprivileged everywhere without extracting loyalty oaths from them first; it also means a shift in the power structure here at home away from the ""military-industrial complex."" With this in mind, this is a solid and valid study, although its tone and method may often discourage the desired ends.