  This paper describes a collaboration between a mathematician and a
compositionist who developed a sequence of collaborative writing assignments
for calculus. This sequence of developmentally-appropriate assignments presents
peer review as a collaborative process that promotes reflection, deepens
understanding, and improves exposition. First, we distinguish writing-to-learn
from writing-in-the-disciplines. Then, we review collaborative writing
pedagogies and explain best practices for teaching peer review. Finally, we
present an implementation plan and examples of student work that illustrate
improved understanding of content and improved exposition.
