This book is intended to introduce a first year graduate student of electrical engineering and/or applied physics to concepts that are critical to understanding the behavior of charge carriers (electrons and holes) in modern nanostructured solid state devices. The student is assumed to have undergraduate background in solid state physics, solid state devices, and quantum mechanics. Many of the topics discussed here are specific to ultrasmall (nanostructured) devices, but some are more general and apply to any solid. This material is the result of the authors teaching a graduate level introductory course on electron theory of solids in three US universities over a period spanning nearly 25 years. It has been his experience that once students are able to grasp the concepts presented here and become comfortable with them, they are able to handle more difficult and specialized topics quite easily. Physics of Nanostructured Solid State Devices introduces readers to theories and concepts such as semi-classical and quantum mechanical descriptions of electron transport, methods for calculations of band structures in solids with applications in calculation of optical constants, and other advanced concepts.