A report on adventure or "junk" playgrounds--areas that provide opportunities for children to build, dig, and play with materials under their own direction--begins with brief sections on the establishment of the original playground in Copenhagen, and the first American experiment, in Minneapolis, in 1950. The main body of the report is concerned with the first four major pioneer projects centered in Liverpool, London, Bristol, and Grimsby. Material is drawn from official reports and publications, newspaper and magazine articles, minute books, personal discussions, and files of the author's work with adventure playgrounds. It details the goals and approaches used; the problems arising from the inevitable untidyness of the playgrounds; and the difficulties of leaders expected to understand, supervise, and provide for the varying needs of all types and ages of children. The final two chapters discuss the language of play and playleadership in respect to role, training, and career structures. A bibliography and list of information and resource centers conclude the report. (Author/MLF)