This book is a critical and analytical survey of the major attempts, in modern philosophy, to deal with the phenomenon of intentionality - those of Descartes, Brentano, Meinong, Husserl, Frege, Russell, Bergmann, Chisholm, and Sellars. By coordinating the semantical approaches to the phenomenon, Dr. Aquila undertakes to provide a basis for dialogue among philosophers of different persuasions. Intentionality has become, since Franz Brentano revived its original medieval use, the standard term describing the mind's apparently paradoxical capacity to relate itself not only to objects existing in the world at all. One approach to the phenomenon emphasizes the mental act. The author argues that the most adequate account involves elements of both approaches. Contemporary treatments tend to formulate problems intentionality primarily in terms of logic and semantics rather than those of metaphysics and phenomenology. Dr. Aquila's effort to coordinate these approaches will make his book useful to students both of analytical philosophy of mind and also of phenomenology.