VLSI, or Very-Large-Scale-Integration, is the practice of combining billions of transistors to create an integrated circuit. At present, VLSI circuits are realised using CMOS technology. However, the demand for ever smaller, more efficient circuits is now pushing the limits of CMOS. Post-CMOS refers to the possible future digital logic technologies beyond the CMOS scaling limits. This book addresses the current state of the art in VLSI technologies and presents potential options for post-CMOS approaches.