The position of caretaker of a school is a many-sided and an important one, and the matter of his selection, supervision, and training have hardly been given the attention they deserve. There have been, in recent years, some valuable local studies in this field, but no survey of national scope has been attempted since 1922. The importance of the custodian, or janitor, in the scheme of public schooling is recognized by those who seek not only a person who can sweep a room or stoke a furnace, but also one who is a skilled sanitarian and an inspiration to youth. This bulletin introduces the subject, reviews previous studies, and presents the recent study conducted through inquiries sent to superintendents in cities having a population of more than 10,000 and in cities of 2,500 to 10,000 persons in 9 representative States. Bulletin sections include: (1) The Present Study--Cities with a population of 100,000 or more, Cities with a population of 30,000 to 100,000, Cities with a population of 10,000 to 30,000, and Communities with a population of 2,500 to 10,000; (2) The Custodian and Safety; (3) Women as custodians; (4) Review and remarks; (5) Changes since 1922; (6) Salaries of Custodians; (7) The custodian of the future; and (8) Selected references. Appended is the Self-Rating Scale for Engineers and Custodians of St. Joseph, Missouri. (Contains 10 footnotes.) [Best copy available has been provided.]