This report draws on two teacher-researchers' yearlong collaboration in co-planning, co-teaching, and co-researching a writers' workshop in a fifth-grade classroom. Alternatives were sought to a more traditional staff development model in which one professional who is considered to have greater expertise and skill supports and coaches another professional. In this case, both individuals were experienced and knowledgeable language arts teachers who were inexperienced at using a writers' workshop approach. As teaching colleagues, they engaged in four critical practices to support their learning: talking about teaching, shared planning and preparation, classroom observations, and training together and training one another. As research colleagues, they inquired about meaningful questions and problems of practice. This report examines questions about what a researcher and an experienced teacher can do and learn together in a restructured context, and about the benefits and difficulties of collaborative professional practice. It explores the collaborative process and discusses issues related to collaborative planning and teaching, using the research process as part of the daily teaching practice. The report also discusses outcomes or products of collaboration. The report concludes with a discussion of ways in which collaboration can play a critical role in supporting new professional roles for teachers and researchers. (Contains 29 references.) (Author/LL)