Somewhat sardonically Reuel Denney adds three more American types to those generalized categories presented in The Lonely Crowd, another book of the national culture to which he contributed. He now considers America, burgeoning with prosperity and leisure and takes the nation to task for the uses it makes of both, contending that we are specialists even in popular pastimes; we have the Participative Purist, with a basement full of tools -- whose products are indistinguishable from the department stores' merchandise. The Spectatorial purist will not sully his hands with participation in hobbies--he is rather the critic who knows all. The Reality purist makes scale-model railroads but disdains the painter of abstract art. Mr. Denny takes a long look at our funny papers, TV entertainment and film fare and concludes that realism is dominant. Sports serve as gate receipts to the universities and as training grounds for industry; the comic strips have been invaded by representational artists, schooled in the advertising marketplace. Grudgingly Mr. Denney concedes that without advertising our economic structure would disintegrate, but he chides the media research boys in witty fashion. An instructor in social sciences at the University of Chicago, Mr. Denny gives us more glittering generalities (against which we are warned by social scientists.) Stephen Vincent Benet said of the many attempts to describe the American Muse, ""All these you are and each is partly you. And none is false and none is wholly true.