This book covers iris and periocular recognition, a prominent field in Biometrics Recognition and Identity Science in the areas of security, computing, and communications research and technologies. Selected topics cover a wide spectrum of current research, focusing on periocular recognition to augment the biometric performance of the iris in unconstrained environments, paving the way for multi-spectral biometric recognition on mobile devices. Divided into three parts, this text covers the most recent research and future directions as well as security related topics.