The aim of this book is to present fundamentals of control systems in an easy way. This book will exploit the topic of Control Systems, which is an interdisciplinary engineering topic. It is purely helpful for Under Graduate (UG) engineering students. It will help students of Electrical and Electronics Engineering (EEE), Electronics and Communication Engineering (ECE) and Computer Science Engineering (CSE). It is meant not only for UG but also for GATE exams also. There are many books on control systems, some of them are very good books from the teachers point of view and some of them are very easy from students point of view. Most of the teachers follow one of these good books and universities prescribe these books in the syllabus. This book is more useful even to extend fundamental knowledge of control system. This book is organized into five chapters: Chapter 1: Transfer functions, Block reduction techniques, Signal flow graphs (SFG) and Mechanical systems Chapter 2: RH criteria, root locus and polar plot Types of input signals, First order system and Second order system Chapter 3: Types of input signals, First order system, Second order system, Error constants and PID controllers Chapter 4: Polar plot, Nyquist plot, Bode plot and compensators Chapter 5: State model, State transition matrix (STM), Observability, Controllability and Diagonalization of matrix Comments and suggestions are invited from readers to improve the quality and standard of the book.