Doctor Krasnoff is convinced that the large scale application of computer methods to medicine will be of great benefit to patients, physicians, and administrators. He shows such enthusiasm and is so ready to accept new technology that this reviewer, who shares his convictions, is tempted to recommend this short book without proper critical appraisal. The temptation is all the greater when it is realized that very few engineers have attempted a simple explanation of the functional anatomy of the digital computer. It is a pity that the lack of background material has made it necessary for a physician to write this book and a shame that he is not just a little better informed. One does not like to blame Krasnoff for the faults of this book; after all, not many engineers could write a good primer of internal medicine; but unfortunately, his search for simplicity has led to inaccuracy.