In the 23rd edition of this classic, until now entitled The American Illustrated Medical Dictionary, the name of the long-time editor has been officially incorporated in the title. This edition is notable, too, for the change in format, a larger page size making possible the presentation of many more entries per page while limiting the volume to a size convenient to handle. It seems that the estimate given of 4,000 new definitions is conservative, for each new edition amazingly succeeds in keeping pace with the ever-increasing medical vocabulary. An innovation which will be appreciated by all more than casual users is the introductory section giving notes on use of the dictionary. The addition of new compilations and the revision of such major parts as the anatomic tables and the section on modern drugs and doses are among the features which make this book the indispensable reference tool it is.