As the inaugural issue in the Leadership for School Improvement (LSI) Special Interest Group (SIG) Book Series, this volume serves as a reflection on the foundations of the field of school improvement. Contents include connections between school improvement and the agency of principals, districts, universities, and policy. This volume will be placed in the school improvement literature with examinations of evolution, trends, policies, and future foci in the field of school improvement. This book is rich in research and literature about school improvement, school effectiveness, and school reform policy and implementation and thus holds significance for educational practitioners, scholars, and policy makers at all levels.