This textbook provides students with an introduction to the fundamentals and applications of solar photovoltaic systems, connecting the theory of solar photovoltaics and the practical applications of this very important source of energy. Chapters are written concisely in straightforward language that provides clear explanations of the concepts and principles, with an emphasis on humanitarian applications of photovoltaic systems and a focus on relatively small size systems that will make the book relatable to readers. It begins with an introduction and overview of the fundamentals of solar cell fabrication, module design, and performance along with an evaluation of solar resources. The book then moves on to address the details of individual components of photovoltaic systems, design of off-grid, hybrid, and distributed photovoltaic systems, and grid-tied photovoltaic systems based on the National Electrical Code (NEC). Coverage also includes a techno-economic analysis of solar photovoltaics, a discussion of the challenges and probable solutions of photovoltaic penetration into the utility grid, and an exploration of the potential of photovoltaic systems. Photovoltaic Systems: Fundamentals and Applications is designed to be used as an introductory textbook and professional training manual offering mathematical and conceptual insights that can be used to teach concepts, aid understanding of fundamentals, and act as a guide for sizing and designing practical systems.