Quantum Theory of Solids presents a concisely-structured tour of the theory relating to chemical bonding and its application to the three most significant topics in solid state physics: semiconductors, magnetism, and superconductivity--topics that have seen major advances in recent years. This is a unique treatment that develops the concepts of quantum theory for the solid state from the basics through to an advanced level, encompassing additional quantum mechanics techniques, such as the variational method and perturbation theory. Written at the senior undergraduate/masters level, it provides an exceptional grounding in the subject.