Encyclopaedia of Solid State Physics has been compiled and edited to incorporate the concepts borrowed from the numerous areas of physics. The concepts have been carefully chosen and described with well defined illustrations and analytically mathematic expressions. The concepts have been described in a lucid style with necessary invaluable background information. Throughout this encyclopaedia, necessary cross-reference system has been maintained to make the reader to understand each concept in a broader scientific contact. The information contained in this book is gleaned from internationally recognized resources. The presentation is marked by a style displaying maturity of writing and bristling with the lucidity and simplicity of the language used by the editor. This Encyclopaedia is written with the objective to enable students to learn all aspects of Physics. This Encyclopaedia will prove to be of great value to the students and teachers of physics. This will also be useful, to some extents, to the scientists and engineers. Content. Physics of Solids; Physics of Liquids and Gases; Reality of Atoms; Model of Atoms; Radioactivity; Atomic Structure; Electrostatic Force; Magnetic Force; Wave Generation and Propagation; Lasers; Mass and Energy; Relativity; The Speed of Light; The Michelson-Morley Experiment; Particles and Waves.