This brief book cannot be recommended for physicians. It is a very simple presentation of a few machines used in medicine such as the electrocardiograph and the electroencephalograph machine. A glossary of 125 machines used by the medical profession is included at the end. The book is written primarily for the intelligent laymen to provide some comprehension of modern biomedical engineering. The work, which can be read in less than one hour, might be of some value to a beginning medical student to afford some orientation into the use of machines in present and future medical practice.