In today’s sensitive environment, there are so many biometric technologies including iris recognition are available for person authentication and are coming of age due to the need to address sensitive security concerns in the 21st century. But, the single biometrics technique is not adequate for person identity recognition due to both sufficiently accurate and user-acceptable for universal application. When capturing an iris image under unconstrained conditions and without user cooperation, the image quality can be highly degraded by poor focus, off-angle view, motion blur, specular reûection (SR), and other artifacts. The noisy iris images increase the intra-individual variations, thus markedly degrading recognition accuracy. To overcome these problems, there are various iris recognition algorithms for noisy iris images. This paper is organized as follows. Part 1 discusses introduction & the technology of iris recognition; Part 2 and Part 3 discusses the application areas; and advantages of iris recognition for personal authentication; Part 4 discusses the importance of noisy iris recognition