When Franz Brentano introduced the concept of intentionality into modern philosophy, he initiated a revolution in philosophical thinking whose effects are still being felt - not least in contemporary developments in the field of cognitive science. Barry Smith's Austrian Philosophy: The Legacy of Franz Brentano is the first extensive study of the philosophy of the Brentano school. The Brentanian philosophy is oriented towards the problem of mental directedness, of how mind relates to objects. Thus in working out their 'theories of objects', the Brentanian philosophers - in contrast to Frege and his successors in the analytic movement - did not abandon psychological concerns in favor of an orientation towards language. Rather, their investigations in ontology proceeded always in tandem with work on the cognitive processes in which objects are experienced. In thus spanning the gulf between psychology and ontology, the Brentano school gave rise to movements of thought such as phenomenology and Gestalt psychology (the term 'Gestalt' was introduced as a technical term of philosophy by Brentano's student Ehrenfels).
The Brentanists enjoyed close relations with Carl Menger and other early members of the Austrian school of economics and Austrian Philosophy contains a detailed study of the interconnections between their work on the general theory of value and subjective theories of value developed in the economic sphere. Brentano's student Kasimir Twardowski initiated the rich tradition of scientifically and logically oriented philosophy in Poland, and the role of Brentanianism in Polish philosophy, and especially in the development of Lesniewski's mereology, is here for the first time subjectedto extended historical treatment. Another Brentano student, Carl Stumpf, was responsible for introducing into philosophy the technical term 'Sachverhalt' or 'state of affairs', and the associated doctrine of realism in logic, too, is shown to have been a special preserve