Jose Celso Barbosa, Luis Munoz Rivera, Jose de Diego and Luis Munoz Marin in separate political biographies which, because the first three crossed frequently, contain considerable duplication; but they can be read independently, a plus for school assignments. Certainly the men and their divergent, still vital, viewpoints are worth knowing. Barbosa was the poor Negro who, after studying medicine at the University of Michigan, became a respected practitioner in San Juan (where being black was a stigma) and the long-time political opponent of Munoz Marin in their common struggle for Puerto Rican self-determination. His position shifted with circumstances; toward the United States he was an ameliorist. Not so as regards race--the gist of his writings was pride in his people. Jose de Diego, favored by birth, was the more radical a poet committed to independence and to Spanish-American culture. Between the two were Munoz father and son, whose roles are better known. They were also the subject of a recent dual biography (61. J-33) which, if fuller, is less penetrating politically (and rather sluggish). Here are quick sketches of the individuals, clear outlines of their positions and programs, as their compatriots saw them.