This book designed for B. Tech and MCA Students. It emphasizes the conceptual understanding of each topic. This book contains lots of solved numerical problems for better understanding of topic followed by unsolved numerical problems for practice. Each chapter contains previous years GATE questions related to the each topic with the answer key. Broadly, the book deals with: 1. Introduction to Computer Organization 2. Register Transfer Logic 3. Data Representation and Logic Design 4. Computer Arithmetic 5. Processor Organization 6. Pipeline and Vector Processing 7. Memory Organization 8. Input Output Organization.