This chapter shows how mentor teachers can foster teacher candidates' thinking by asking them to describe, interpret, strategize and justify their teaching. Encouraging reflection is one of the most important responsibilities of mentor teachers. Teacher preparation programs employ multiple approaches to developing the practice of reflection, including reflecting on classroom artifacts, microteaching, and actual classroom teaching. The development and organization of knowledge in individual teachers is not constructed around theories; it is constructed around classroom experiences. Two distinctly different types of practitioner reflection are widely recognized in teacher education: reflection-in-action and reflection-on-action. The type of reflection most important to mentoring in classrooms is reflection-in-action. The second type of reflection is reflection-on-action. It occurs later, often outside the classroom well after a lesson is taught. Both occur as part of the reflective process in the recursive cycles of experiential learning and both types of reflection contribute to the internalization of teaching schemas for candidates.