In his usual clear, thorough fashion, Berger explores the history and controversial aspects both of heart transplants and of artificial implants. Since the development of the heart-lung machine at mid-century, researchers have been working toward an artificial device that is portable as well as reliable; several different models are described, though the Jarvik-7 seems to be by far the most widely used, and Berger appends a chart listing every artificial heart recipient through March 1987, with information on each patient's subsequent (usually brief) medical history. Heart transplants are not very much more common; and because donors are often hard to find (so great is the shortage that ""about 1/3 of all transplant candidates die while waiting for a new heart""), artificial hearts have found a use as temporary installations, put in to buy time. Berger devotes a chapter to the ethical questions raised by this strategy, and another to the psychological trauma many heart recipients suffer. Other books, such as Skurzynski's Bionic Parts for People, treat some of these topics, but this expands the discussion. Index, bibliography.