Biometric security systems is core subject for PG students in information security, computer science, cyber security, forensic science and other related streams etc. This book is primarily intended to serve as a beginner’s textbook in accordance with the syllabus of biometric security offered by CSVTU and various universities in India. In this book, a significant effort has been made to find simple ways to develop theoretical aspects of biometric systems. Neat and clear diagrams have been used for explanations. Author has also introduced case study and biometric programming concept in java. The author hopes that the book will fulfill the need of the readers and would welcome any suggestions towards the improvement of the book.