Policy implementation studies have examined how teachers experience and respond to top-down education reforms. However, experiences of pedagogical change from the inside out remain largely unexplored. This book analyses the experiences of a group of teachers in Mexican public middle schools as participants in a project of pedagogical transformation from the inside out. These teachers experienced substantial changes in their practice and are redefining their relationship with the wider educational system. The author argues that a focus on the instructional core is a productive way to link teachers’ drive to improve educational opportunities for their students to the wider institutional mandate to reform schools on a large scale. In order to enable and support teachers’ efforts to transform their practice, he calls for the creation of bargaining arenas where actors at different levels of the educational system engage in collective discussion and decision making. The work presented here will appeal to researchers, policy makers, and practitioners interested in examining or promoting education reform from the inside out.