The past few decades have witnessed remarkable growth and progress in our knowledge concerning the structure and properties of aperiodic systems at a microscopic level. The present volume provides a timely overview of the current state of the art on the structure, electronic and magnetic properties of aperiodic materials, including structural inhomogeniety. It also describes the theoretical calculation methodology. The subject is approached both from the basic science and the applied engineering points of view. Many references, illustrations and tables assist specialists and non-specialists alike to gain access to the growing body of essential information.