We are pleased to place our book "Cyber law" before the academic community .This book has come to satisfy the long felt need of the students. This hand book on cyber law for students has been prepared to enable easy learning of cyber law. The book comprises the concept of cyber law, cyber crimes, security aspects, evidences and Information Technology Act which are applicable in real time applications. Thus, this book would be useful to create an awareness of these aspects.Cyber law has emerged as an interesting area for the students and teaching members. This book is intended as a text book for the student of B.COM, B.COM CA, B.COM PA, B.COM IT, BBA and BBM, Courses. Although several books are available on this subject, the authors promoted to write this book very intention of presenting the concepts and cyber law in a lucid style to enable the students to learn the subject easily. Therefore, this book has been written keeping in mind the problem faced by the commerce and management stream students. Adequate care has been taken to reduce the complex vocabulary to the minimum.