This book deals with 3D nanodevices such as nanowire and nanosheet transistors at 7 nm and smaller technology nodes. It discusses technology computer-aided design (TCAD) simulations of stress- and strain-engineered advanced semiconductor devices, including III-nitride and RF FDSOI CMOS, for flexible and stretchable electronics. The book focuses on how to set up 3D TCAD simulation tools, from mask layout to process and device simulation, including fabless intelligent manufacturing. The simulation examples chosen are from the most popular devices in use today and provide useful technology and device physics insights. In order to extend the role of TCAD in the More-than-Moore era, the design issues related to strain engineering for flexible and stretchable electronics have been introduced for the first time.