Textbook in PDF format This book provides a comprehensive exploration of contact electrification across solid-solid, solid-liquid, and gas-solid interfaces. It looks into the underlying physics mechanisms, offering theoretical models and experimental methods to quantify and understand this ubiquitous yet complex phenomenon. Covering fundamental concepts such as triboelectricity, energy band models, and tribovoltaic effects, the book discusses the interactions and charge transfer processes that occur at various interfaces. Special attention is given to the role of material properties, electron transfer dynamics, and external factors such as surface roughness and environmental conditions. Each chapter builds upon foundational principles to provide a cohesive framework for understanding both the beneficial applications and potential drawbacks of contact electrification