With its large and heterogeneous Indian population, the Los Angeles area offers an excellent opportunity to study patterns in the origin, growth, and structure of Indian voluntary associations, and the leisure time institutions. Since the 1920's more than 100 Indian voluntary associations formed in the area. Established groups influenced the formation, content, and development of subsequent groups, which tended to be special purpose rather than multipurpose and which often duplicated objectives of established groups in an attempt to remedy actual or perceived shortcomings. Overlapping memberships, whereby a person belonged to two or more voluntary organizations, was one of several mechanisms in a complex network that linked Indian organizations to each other much more than to any non-Indian entity. While overlapping memberships improved communication and transferred knowledge between groups, they also created problems, such as spreading talent too thin and dividing loyalties. Contacts outside the network of Indian groups increased with government funding of anti-poverty-type programs and the growing need for outside help in order for groups to operate successfully. Investigators of urban Indian phenomena should continue to document the intrinsic qualities of leisure time adaptations and discover the conditions that determine their development. (JH)