This book is an undergraduate level textbook presenting a thorough discussion of state-of-the-art digital devices and circuits. It supplements our Electronic Devices and Amplifier Circuits, ISBN 0-9744239-4-7. It is self-contained; begins with the basics and ends with the latest developments of the digital technology. The intent is to prepare the reader for advanced digital circuit design and programming the powerful Complex Programmable Logic Devices (CPLDs), and Field Programmable Gate Arrays (FPGAs).