The goal of the Mathematicians Writing for Teachers Conference is to plan and implement a conference at which classroom teachers, mathematics educators, mathematicians, and community college faculty work collaboratively to consider critical questions about content and pedagogy in the mathematics education of K-8 teachers. These discussions will be grounded by co-teaching actual professional development sessions, through observing each other teaching, and through debriefing teaching sessions based on observations and videotape. The participants will produce an emerging set of principles and approaches to professional development for K-8 teachers that connect important mathematics content and ideas to classroom teaching and learning.