This revised guide is intended for use by both beginning and experienced church and synagogue librarians. Based on the latest edition of the Dewey Decimal System, the classification system that is recommended focuses on those subjects which would most likely be found in a congregational library. It is suggested that synagogue librarians may find it useful to use this classification system as a supplement to one of the Jewish classifications already published (as listed in this guide's 10-item bibliography). The major classification headings are: (1) General Works; (2) Philosophy, Ethics, Psychology; (3) Religion--General Works; (4) Religion--Natural Theology; (5) Religion--the Bible; (6) Religion--Doctrinal; (7) Religion--Devotional; (8) Religion--Pastoral, Parochial; (9) Religion--Church--Institutions and Work; (10) Religion--Church History; (11) Religion--Denominations and Sects; (12) Religion--Non-Christian; (13) Religion--Judaism; (14) Social Science; (15) Language; (16) Pure Science; (17) Useful Arts, Technology, Applied Science; (18) Fine Arts, Recreation; (19) Literature; and (20) Geography, History, Biography. The guide provides step-by-step instructions for classifying a collection of books as well as a brief introduction to the purposes of classification. (10 references) (SD)