The usefulness of digital electronics can be seen in everyday human life. Most of the modern devices and equipments such as computers, microprocessors, memory units, mobiles, TV, digital clocks etc., are based on the principles of digital electronics. It is not possible to construct these products without digital electronics. Day by day application areas of digital electronics have been increasing. Starting from the fabrication of vacuum tubes to transistors, the science has moved rapidly to fabricate integrated circuits, which, in turn, has paved the way for generating micro-processors and super computers. It is a matter of immense pleasure to bring out this book of 'Basics of Computer Architecture & Digital Electronics'. This book gives an idea how different hardware components organize together to form a computer system. It also provides the knowledge of computer architecture that is structure and behavior of the various functional modules of the computer. Student-friendly writing style and large number of typical examples have been worked out in this book. This book serve the needs of students of Science, Computer science and engineering.