This pamphlet on getting and keeping members is the twelfth of 16 in a series to provide leaders in adult activities with sound introductory material to give practical help in using a method of adult education or working in a particular area. Its objective is to help leaders of adult groups find and keep members. Eight articles and how-tos are included. "Why Do People Join?" presents results of interviews with a psychologist and two sociologists regarding what people want from group affiliation. The two chapters on "On Principle and Policy" and "The Membership Committee" are intended to give guidance in organizing for membership growth. A variety of suggestions for involving people in an organization and keeping them involved are made in "The Crucial Job of Recruiting,""Keeping Your Members," and "The Problem of Dropped Members.""A Measure of Attendance" takes a somewhat unconventional view that emphasizes quality rather than numbers. "Who Belongs to What in a Big City" highlights findings from a study of participation in Detroit organizations and offers some facts to challenge impressions about the role of organizations in the life of a metropolis. (YLB)