Biometrics-based authentication and identification are emerging as the most reliable method to authenticate and identify individuals. Biometrics requires that the person to be identified be physically present at the point-of-identification and relies on something which you are or you do to provide better security, increased efficiency, and improved accuracy. Automated biometrics deals with physiological or behavioural characteristics such as fingerprints, signature, palmprint, iris, hand, voice and face that can be used to authenticate a person’s identity or establish an identity from a database. With rapid progress in electronic and Internet commerce, there is also a growing need to authenticate the identity of a person for secure transaction processing. Designing an automated biometrics system to handle large population identification, accuracy and reliability of authentication are challenging tasks. At the time of writing, there are over ten different biometrics systems that are either widely used or under development. Some automated biometrics, such as fingerprint identification and speaker verification, have received considerable attention and some issues like face recognition and iris-based authentication have been studied extensively resulting in successful development of biometrics systems in commercial applications. However, very few books are exclusively devoted to such issues of automated biometrics. This text systematically introduces the technologies and systems, and explores how to design the corresponding systems with in-depth discussion. The issues addressed are relevant to many fundamental concerns of both researchers and practitioners of automated biometrics in computer and system security.