"Microprocessor, Microcomputer and their Applications, 4/e", in three parts, covers the hardware, software and the applications of microcomputers. This book covers single chip microcomputers (microcontrollers) emphasizing on the architecture, memory organization, programming technique and a large number of programming examples. Interfacing techniques have been explained clearly with the aid of diagrams, charts and tables along with the input/output devices and controlling and peripheral devices. The book is intended for undergraduate and postgraduate students of Computer Science and Engineering, Electrical Engineering, Electronics and Allied fields of engineering and sciences. Researchers and professionals will also find this book beneficial.