Collaboration between student writers appears in various guises: small groups discuss each writer's paper in turn; a pair of classmates exchange papers to read and critique; a whole class evaluates a few students* papers based on an established set of criteria; a student shares her paper with a peer tutor at a writing center. All of these situations attempt to capture and build on the energy and shared learning that occur when students work together. And yet, while both the writing center and the classroom aim for collaborative learning, each context places the students in a different relationship. In the classroom, the students work together as peers under the teacher's guidance; in the writing center, students must work to overcome the disparity of authority inherent in their given roles of tutor and tutee. The difficulty for writing tutors lies in balancing their more powerful position as tutor with the goals of peer collaboration. Thus, collaboration in writing takes different forms and requires different skills in the contexts of classroom and writing center. This paper will use a study of a high school writing center program to illustrate and explain these differences. We hope that this discussion will provide insight into how writing tutors perceive and cope with their roles in a writing center and how the collaboration that occurs in a writing center affects students as writers and as people. Kenneth Bruffee's definition of collaborative learning provides a framework for understanding the difference between classroom and writing center collaboration. In his article, "Collaborative Learning and the Conversation of Mankind,1 " Kenneth Bruffee explains that " Collaborative learning provides a social context in which normal discourse occurs: a community of knowledgeable peers" (644). Adapting Thomas Kuhn' s theories about the scientific community, Bruffee emphasizes that a group of people together determine the accepted knowledge, the "normal discourse"