The transfer of educational research into instructional practice through educational development is a complex process. A longitudinal study of five schools working with two development efforts illustrates the complexity of this process. Each development effort sought to create an "approach" that external linking agents could use to help schools modify their programs in specific areas. Data come from two years of participant observation and numerous interviews with teachers and administrators in the schools as well as linking agents from the development efforts. The study suggests that: (1) the knowledge transfer process consisted of four analytically distinct stages that overlapped in time; (2) developers rely on practical knowledge in different ways; and (3) teachers' practical knowledge is grounded in a pragmatic, concrete occupational culture. The knowledge transfer process is characterized by tension between research and practical knowledge which is worked out in different ways at each stage. (Author/GK)