Rooted in nearly five decades of scholarly research, transformative learning theory explores how individuals construct and reinterpret their experiences, leading to profound change. This chapter delves into the foundational principles of transformative learning within adult education, highlighting its significance and broad applications. It starts with a definition of transformative learning, moves through traditional perspectives, reviews effective practices, addresses critiques, and calls for a unified theory and metatheory. It concludes with an overview of recent scholarly contributions. The chapter outlines the evolving nature of transformative learning, emphasizing its theoretical developments and the ongoing efforts to synthesize various perspectives. As the field progresses, the pivotal role of transformative learning in fostering deep and meaningful change in adult education is continually reinforced.