This study addressed the question of why, to what extent, and under what conditions teachers fully implement and adapt instructional innovations. The subjects, a group of 24 ninth grade content area teachers, were seen to have implemented a particular set of reading innovations only to a limited degree. Five major themes were revealed as having an impact on teachers' use and adaptation of content reading innovations: (1) time and pressures on the teachers; (2) informal friendship systems within the school which in turn seemed to be influenced by organizational patterns in the school; (3) social/political factors in the school; (4) the existence of and the nature of the inservice support system; and (5) the subject that was taught by the teachers. Suggestions are made on several factors which should be taken into account if staff development programs are to impact on teachers' use and adaptation of innovations. Appendices include the interview form. (JD)