This article examines a 2-year process of integrating Lesson Study--a form of teacher-led professional development--into an introductory course on the principles of teaching for students majoring in early childhood education. The course is taught in conjunction with beginning practicum work in area schools. We describe obstacles, modifications, and outcomes as we adapted the Lesson-Study process to help preservice teachers pay closer attention to instructional strategies (such as questioning techniques, anticipating student responses, and how lesson flow affects student understanding), and become more comfortable with constructive criticism by focusing on the lesson "plan" rather than the teacher. (Contains 2 tables.)