This book presents the underlying principles of the linear and nonlinear optical properties of materials. It is divided into two parts. The first part, Linear Optics, discusses optical properties, implementation and applications of noble metals, metal oxides, magnetic oxides and organic materials. The author has also included his original research work and its interesting outcome. Part two, Nonlinear Optics, covers the general concepts of electromagnetic theory and wave propagation in a nonlinear medium. Finally, the author discusses second harmonic generation, phase matching, optical parametric interactions, different frequency generation, sum frequency generation, tunable lasers and optical resonant oscillators. There are illustrations, examples and problem sets with solutions for each chapter, which makes it a helpful resource for problem solving. The book is suitable for students and researchers in optical physics and related fields.