This is an attempt to include under one cover all important terms and concepts related to psychiatry since the time of Hippocrates. Words that are obsolete are so indicated, and those that are tending to disappear are marked obsolescent. The volume, which is the work of many collaborators, contains seven thousand, five hundred title entries, including some biographic references. The work is obviously fundamentally useful to every worker in the field that it concerns. Especially useful are the references to writings in which terms first became established.