In this chapter, the authors outlined a framework for teacher development based on three broadly accepted precepts of teacher development: development in context, development toward complexity, and development of teacher thinking. They describes how mentoring can facilitate the development of a beginning teacher candidate with little or no experience all the way to a teacher leader who can design new instructional systems, who possesses a solid understanding of teacher development, and who has the capacity to mentor both teacher candidates and teachers. To foster teacher development and learning, practice must always be moving toward complexity. Fostering the integration of existing schemas into larger and more coherent networks depends first on the nature of teacher candidates' experiences. It works well for fostering relationships and initiating a vigorous discussion of teacher development. The chapter also presents an overview of the key concepts discussed in this book.