In this monograph the author endeavors to prove that many cases considered by Kraepelin and his school as belonging to manic-depressive and periodic insanity really belong to the disease first thoroughly described by Kahlbaum as catatonia. By the latter term Urstein does not mean the so-called form of catatonic dementia præcox; he recognizes catatonia as an independent disease, which may appear under various guises. He differs radically from Kraepelin and supports his contention by publishing in extenso case histories which have been accurately recorded in the Schweizerhof asylum under the direction of the deceased Henry Laehr. The greater portion of the monograph (545 pages) is devoted to a reproduction of these histories with comments. Students of psychiatry, whether they agree with the author's interpretation or not, will undoubtedly enjoy reading these.