Professional development schools (PDSs) are a specific type of school-university partnership designed to support teacher preparation, professional development, inquiry and research, and student learning. Due to active teacher engagement in PDS work over the past three decades, teacher leader practice and development has emerged as a serendipitous outcome of PDS partnerships. Originally published in the book "Teacher Leadership in Professional Development Schools," the first chapter provides an overview of professional development schools before offering a brief history of PDS in the United States. Chapter 2 defines teacher leadership in PDSs, introduces distributed leadership theory, and provides a brief history of teacher leadership in the United States before asserting several characteristics that render PDSs ideal settings for studying teacher leadership. [The two manuscripts provided in this document were published in the book: "Teacher Leadership in Professional Development Schools," edited by J. Hunzicker, Emerald Publishing, 2018, pp.1-37.]