This volume contains a number of studies on professional development that blend issues in mathematics education with issues of equity. The composition of U.S. schools is becoming more diverse while the teaching force remains largely White and middle class. Teachers are thus meeting students who have backgrounds significantly different from their own. Teaching these diverse students effectively involves attending to multiple issues that impact classroom performance, as well as developing multiple knowledge bases including knowledge of content, and knowledge of students and their communities. Professional development must therefore address both mathematics and equity so that student learning can be enhanced.