This book provides readers with the knowledge in fundamentals of nanoelectronic devices. The authors build the principles of nanoelectronic devices based on those of microelectronic devices wherever possible and introduce the inherently nanoelectronic principles gradually. They briefly review quantum mechanics and solid-state physics that can form the basis of semiconductor device physics. The book also covers the basics of electron transport and p¿n junctions, develops the operations of MOS capacitors and MOSFETs, and introduces some basic CMOS circuits. The last chapter is devoted to the nano-biotechnology application of field-effect transistors.