Intended to motivate and assist librarians in taking a new approach to library services for adolescents of junior high and high school age, this handbook (1) outlines the benefits of youth participation in school and public libraries; (2) describes some existing programs, including youth participation in library planning and policy, publication of book reviews and library newsletters, storytelling and puppetry, production of a library promotional videotape, and administration of a library-affiliated youth center; and (3) provides guidelines for implementing youth programs, covering such issues as selecting adult facilitators, obtaining administrative support, recruitment, training, and establishing trust. A preface presents background information on the activities of the American Library Association (ALA) Young Adult Services Division (YASD) Youth Participation in Library Decision-Making Committee, and a foreword by Barbara Cialone describes her personal experience with "Teenage Express," a youth magazine produced in Spring Valley, New York. Appendices present sketches of 13 other library youth programs, the YASD guidelines for youth participation in library decision making, annotated lists of resource organizations for youth projects and relevant National Commission on Resources for Youth (NCRY) publications, a list of libraries that report having youth participation programs, the "Teenage Express" policy statement, and a list of 3 periodicals and 10 other publications on youth participation. (ESR)