The main objective of this book is to present the subject in a simple and lucid manner and make it as informative as possible. This book consists of seven chapters—First to fourth chapters focuses on overview, process concept, CPU scheduling, memory management of operating system. Fifth to seventh chapters highlights on file system, Deadlocks and process management and synchronization. Each chapter has been started with introductory information. This book is an indispensable for all of them who are having the relationship with computer related activities.