This book describes building blocks of computer,register transfer language and architecture of a simple processor in easy to understand language with ample number of illustrations.CPU organization,Assembly language programms and various arithmetic algorithms are all explained in such a manner,that students can understand these technical topics very easily. Input /Output organization,Memory organization are some of the hardware features of a computer which are evoling everyday.Concepts behind these systems are covered with maximum number of diagrams and easy to understand examples.   A special characteristic of this book is that large number of objective questions and solved sample papers are included at the end of each chapter.Readers can evaluate their progress easily by solving these papers and comparing answers