Abortion is at once a moral, medical, legal, sociological, philosophical, demographic and psychological problem, not readily amenable to one-dimensional thinking. . . . My aim is to write a calm book, trying to bring out the full complexity of the problem."" Callahan's aim is most creditably accomplished in this hefty, conscientious, and well-crafted study of abortion as theoretical issue and practical reality. A major spokesman for a ""new"" Catholicism who has exposed The Mind of the Catholic Layman (1963), questioned Honesty in the Church (1965), and presented The Catholic Case for Contraception (1969), Callahan is currently Director of the Institute for Society, Ethics and the Life Sciences. The beauty of his approach here is that it is genuinely catholic: he marshals the evidence and arguments on all sides of the question, he presents the available data on the actual effects of different abortion laws around the world, and he attempts to derive ""objective"" criteria for the moral and legal evaluation of the different alternatives. But Callahan is not one to straddle even so formidable a mound of complexities; after evaluating and criticizing the Roman Catholic position (""It does not allow a sufficient place in its theoretical approach to the consideration and weighing of other values than that of the right to life"") and the opposite-extreme ""abortion-on-request"" argument (""Women should be accorded the right of control over their procreative faculties--as long as the language of 'absolute' rights is avoided""), Callahan sketches what would seem the rudiments of a good legal and a good moral policy toward abortion. A permissive law would make abortions available cheaply and equitably to women who want them, but it would be women's responsibility to weigh seriously their moral choices and society's responsibility to improve contraception and welfare programs to make the choices other than abortion desirable. An excellent comprehensive examination of an issue whose time is now.