This book provides ample coverage of theoretical and experimental state-of-the-art work as well as new trends and directions in biometrics. It offers students and software engineers a thorough understanding of how some core building blocks of a multi-biometric system are implemented. While the book covers a range of biometric traits including facial geometry, 3D ear form, fingerprints, vein structure, voice, and gait, its main emphasis is on multi-sensory and multi-modal face biometrics algorithms and systems. The four main sections of the book address new and emerging face biometrics; the challenges of identification in variable light and outdoor operating scenarios; multi-modal face biometrics, integrating voice, ear, and gait modalities; and multi-biometric fusion methodologies.