In the ever-evolving landscape of semiconductor technology, the pursuit of smaller, faster, and more efficient devices has been a driving force behind innovation. Among the myriad advancements, the emergence of the Junctionless Gate-All-Around (GAA) Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) stands out as a transformative milestone. This book is an exploration of the Junctionless GAA MOSFET, a breakthrough that promises to redefine the boundaries of conventional transistor design. From its conceptual genesis to its practical implications across diverse industries, this book aims to unravel the intricacies of this cutting-edge technology. With a blend of technical insights, practical applications, and forward-looking perspectives, it seeks to illuminate the path toward a future where Junctionless GAA MOSFETs play a pivotal role in shaping the semiconductor landscape.