Becoming a Reflective Mathematics Teacher: A Guide for Observations and Self-Assessment offers what every mathematics teacher educator or supervisor has been looking for. Ideally suited for use with students who are taking a methods course or who are student teaching, this activity-oriented, research-based text: *supplies detailed observation instruments that preservice teachers can use when they observe other teachers. Each instrument focuses on a critical aspect of instructional practice in mathematics (e.g., tasks, learning environment, discourse). In addition, it requires the observer to make conjectures regarding the teachers' underlying cognitions (e.g., knowledge, beliefs, goals) that might account for the instructional practice they observe. *offers reflective activities that provide a structure through which beginning teachers can think about their teaching in an insightful, thorough, and productive manner. Students can work through the activities over the period of a year. The structured observations and reflective activities are modular, and the framework applies to all observations of teaching, no matter what the instructional content. *includes guidelines and instruments for supervisors to use when observing, conferencing with, and assessing beginning or student teachers. The unique aspect of these guidelines and instruments is the link they make between teachers' cognitions and their instructional practice. All instruments and suggested activities are couched within a highly effective framework for teacher reflection and self-assessment that was developed in the spirit of the NCTM professional teaching standards. This framework is grounded in a cognitive perspective on learner-centered teaching. In Part I, the framework is explained and its validity is documented. Part II shows how teachers can use the framework to observe other teachers' classroom work, and to reflect on their own teaching. Part III offers case studies to help readers see how the method works.