This booklet describes one of the earliest staff development models to support school-based improvement, the RPTIM model. The letters "RPTIM" represent the five stages of the school-based approach to staff development--readiness, planning, training, implementation, and maintenance. The model is based on the belief that the school is the primary unit of change and that careful long-range planning is crucial to realizing improvement. The model advocates the development of commitment, ownership, and a positive, supportive school climate; the continuous involvement of all staff members in professional development; and the design of inservice education based on adult learning theories. The first five sections provide information on the five stages of the model. Section 6 stresses that the stages are both sequential and interactive. Five key elements are reviewed: the use of expert help, the development of ownership and commitment, the full involvement of the principal, a focus on staff development to support school improvement, and an emphasis on research. A brief final section offers a general summing up. (LMI)