As noted in the Preface, social scientists are entering a period of shared realization that the United States is in a crucial period of transition. "Trans-action" magazine, a pioneer in social programs for changing the society, has dedicated itself for 7 years to the task of reporting the strains and conflicts within the American system and has published a series of books consisting of articles that originally appeared in the magazine. The series deals with social changes such as organizational life-styles, concepts of human ability and intelligence, changing patterns of norms and morals, and the relationship of social conditions to physical and biological environments. As one in the series, this book contains 5 essays on American Indians, 2 on Mexican Americans, and 4 on Puerto Ricans. (JB)