This doctoral dissertation explored how integrating the essential elements of Lesson Study as a powerful intervention in the pre-service mathematics teacher education contributes to prospective teachersÕ facility in realizing their theoretical knowledge in the actual practice of teaching. Whereas Lesson study is widely being performed in in-service mathematics teacher education, this investigation sought to explore practices in Japanese pre-service teacher education environments that potentially nurture amongst the prospective teachers their facility in being able to successfully participate in Lesson Study activities as they commence their actual in-service teaching. Thus, in this this investigation, the focal research question was ÒHow are the essential elements of Lesson Study integrated in pre-service teacher education in Japan?Ó