Silicon CMOS technology continues to drive progress in electronics, but device scaling is rapidly taking the metal oxide semiconductor field-effect transistor (MOSFET) to its limit. A variety of new devices are emerging as candidates to replace MOSFETs and continue the trend downward to molecular dimensions. Nanoscale MOSFET engineering, is still governed by techniques originally developed to treat microscale devices. To push MOSFETs to their limits and to explore devices that may complement or even supplant them, this timely reference presents a clear understanding of device physics at the nano/molecular scale.