This book is a collection of six case studies of teacher agency in action, centering on voices of educators who engaged in activist work throughout the history of education in the US. Through a lens of teacher agency and resistance, chapter authors explore the stories of individual educators to determine how particular historical and cultural contexts contributed to these educators' activist efforts. By analyzing specific modes and methods of resistance found within diverse communities throughout the last century of US education, this book helps to identify and place into theoretical and historical context an underemphasized narrative of professional teacher-activists within American education.