This book is designed to serve as a textbook for advanced graduate and postgraduate students enrolled in the physics, engineering physics or material science and engineering course. It covers the fundamental and advanced topics of plasmas and ion beams, plasma ion sources and ion beam extraction from plasmas. It also discusses the interaction of low-energy ion beams derived from plasmas, and their utilization for engineering materials and bringing about novel properties in them. It further discusses the applications of these materials in space, electronic and field emission devices. Various other topics covered in this book are generation of broad and focused low-energy micro-ion beamlets and their control, creation of atomically heterogeneous systems including case studies on modifying electrical, optical and field emission properties of materials. End-of-chapter questions will aid to self-learning among students. The detailed coverage and pedagogical tools make this an ideal textbook for students enrolled in a physics, engineering physics or material science and engineering course. It will also be a good reference book for researchers and professionals in the area of material science and engineering.