The process of curriculum development involves two phases: transformation of research findings into curriculum material by external developers and implementation of curriculum materials by teachers. In a study of the development of an eighth grade biology unit in Israel, the authors examined the characteristics of and relationships between the activities of external developers and teachers. Analysis of the first phase, material development by an external group, involved examination of various versions of the curriculum material, minutes of meetings, and comments of development team members. It was found that the developers made changes in transforming research in the field of biology into eighth grade level curriculum material. These changes included simplifications of content, omissions, and changes in style and forms of expression. Analysis of the second phase, implementation of the unit by teachers, involved a survey of the 20 teachers who used the unit. It was found that the teachers spent more time on the unit than was specified in the teacher's guide, used more teaching strategies than were outlined in the guide, and emphasized approximately the same content as was stressed in the guide. Additional research is needed to explore the impact of personal characteristics of developers and teachers upon the process of curriculum development. (AV)