This book discusses one possible solution to the key issue in electronics engineering - the approaching limits of CMOS scaling - by taking advantage of the tendency of Schottky contacts to form at channel interfaces in nanoscale devices. Rather than suppressing this phenomenon, a functionality-enhanced device exploits it to increase switching functionality. These devices are Multiple-Independent-Gate-Field-Effect-Transistors, and other related nanoscale devices, whose polarity is electrostatically controllable. The functionality enhancement of these devices increases computational performance (function) per unit area and leads to circuits with better density, performance and energy efficiency. The book provides thorough and systematic coverage of enhanced-functionality devices and their use in proof-of-concept circuits and architectures. The theory and materials science behind these devices are addressed in detail, and various experimental fabrication techniques are explored. In addition, the potential applications of functionality-enhanced devices are outlined with a specific emphasis on circuit design, design automation and benchmarking.