A Volume in The Montana Mathematics Enthusiast: Monograph Series in Mathematics Education Series Editor Bharath Sriraman, The University of Montana The intent of this monograph is to showcase successful implementation of mathematical discourse in the classroom. Some questions that might be addressed are: * How does a teacher begin to learn about using discourse purposefully to improve mathematics teaching and learning? * How is discourse interwoven into professional development content courses to provide teachers with the tools necessary to begin using discourse in their own classrooms? * What does a discourse-rich classroom look like and how is it different from other classrooms, from both the teacher's and the students' perspectives? * How can teachers of pre-service teachers integrate discourse into their content and methods courses? * How can we use discourse research to inform work with teachers, both pre- and in-service, for example, to help them know how to respond to elicited knowledge from students in their classrooms? * What are the discourse challenges in on-line mathematics courses offered for professional development? Can on-line classrooms also be discourse-rich? What would that look like? * In what ways does mathematical discourse differ from discourse in general?