This book reviews the results of experimental research into mesoscopic devices, and develops a detailed theoretical framework for understanding their behaviour. The authors begin by discussing the key observable phenomena in nanostructures, including phase interference and weak localization. They then describe quantum confined systems, transmission in nanostructures, quantum dots and single electron phenomena. Separate chapters are devoted to interference in diffusive transport and temperature decay of fluctuations, and the book concludes with a chapter on non-equilibrium transport and nanodevices. Throughout, the authors interweave experimental results with the appropriate theoretical formalism. The book will be of great interest to graduate students taking courses in mesoscopic physics or nanoelectronics, as well as to anyone working on semiconductor nanostructures or the development of new ultrasmall devices.