This paper examines the concept of identity from philosophical, personal, and territorial perspectives. In the first section an historical perspective on identity is explored through the writings of Plato, Dupius, Josephus, and Thut. Twentieth century models of identity are related to the concepts of these writers of ancient Greece. In the second section, on personal identity, the ideas of modern theorists are highlighted, particularly the work of Erickson. In the following sections, the concepts of identity confusion and group identity are related to the definition of personal identity. The formation of individual identity is discussed in the context of family influence. Finally, future developments in the concept of personal identity are discussed. (MCF)