This issue of "The Progress of Education Reform" highlights data and research on why teachers leave, how attrition affects teacher shortages across the nation and the importance of working conditions for student performance. It focuses on: (1) reasons for teacher turnover; (2) elements of working conditions related to teacher retention and student learning; and (3) the impact of teacher turnover on the teacher shortage crisis. It also includes links to additional resources on teacher attrition and teacher working conditions.