In a naive sense it seems that there could be nothing simpler than to 'know thyself' yet a philosophical elucidation of the process by which one comes to know oneself is quite elusive. In this book Gregg Ten Elshof deals with the epistemology of introspection; whether and to what extent self-knowledge can appropriately be thought of as a species of perception. Assessing the suggestion that we, at least sometimes, come to acquire significant knowledge about ourselves, by observation, in very much the same way that we sometimes come to know things about the external world; this book explains the perceptual/observational model of introspection and contrasts it with its more prominent competitors.