Updated examples (i.e. 1975 developments on Dr. Barnard's new twin-heart operations) constitute the chief difference between this and previous reports from the frontiers of medicine. Aylesworth surveys past and projected work on well-publicized, life-extending projects such as artificial parts (there's one that enables blind people to participate in track meets), transplants, freezing the dead for future revival (or just lowering everyone's temperature to prolong life) and cloning which could produce exact reproductions of ""an Einstein or a Beethoven or a Catfish Hunter."" Test tube babies and such matters as prenatal sex determination are also mentioned, and throughout Aylesworth covers background biology, philosophical questions and ingenious devices with the same once-over lightness. Spare parts.