Twenty-three editions of Gray's Anatomy, a medical classic, have appeared since the publication of the first English edition in 1858. The volume has had several editors but throughout the course of its development has maintained a constant approach to this fundamental medical book. In the present edition the various sections have been brought down to date by the incorporation of new additions to anatomic knowledge, particularly in the sections on embryology and on the ductless glands, where research has centered in the last few years. In the revision of the text of the section on the central nervous system, Dr. David McK. Rioch of Harvard University Medical School has carried the responsibility. Some new illustrations have been added and older ones replaced. The Basle anatomical nomenclature in English is followed. The current volume is prefaced by a portrait and a brief biography of Henry Gray, author of the first edition.