Prof. Glanz’s book on action research will be of great value to professors of educational leadership and their students, as well as school leaders and teachers interested in improving professional practice, schools, and student learning. This user-friendly text succeeds not only in explaining the action research process but also in demonstrating the meaning and value of that process. Key features of the book are its readability, concrete suggestions for conducting action research, and myriad questions and activities that promote reader reflection. The fourth edition includes a significant amount of new material, making it a vital resource, even for those familiar with previous editions.