In this book, Operating principles, clinical applications, and future promises of OCTA are clearly explained by world-renowned original developers of the technology. Part I, Section 1 of the Atlas exposes the basic principles of OCT angiography, the methods and technology, the interpretation of OCTA imaging, the vascular anatomy of retina, and the clinical applications from an angiographic perspective. In Part II provide a general update on the state of clinical OCT angiography research in a variety of retinal, choroid, and anterior chamber disorders. Part III describes the future clinical applications and implications of next generation of devices.