Telexistence is a fundamental concept which refers to the general technology that enables a human being to have a real-time sensation of being at a place other than where he or she actually exists, while being able to interact with the remote environment, which may be real, virtual, or a combination of both. It also refers to an advanced type of teleoperation system that enables an operator at the control to perform remote tasks dexterously with the feeling of existing in a surrogate robot working in a remote environment. Telexistence in the real remote environment through a virtual environment is also possible.This book is the first book on telexistence written by the inventor of the concept of this emerging technology. It introduces the concept of telexistence, explains how this concept can be realized, illustrates precisely real examples of the realization of the concept, and determines its future advancement.