If we look at Brentano's publications, we quickly see that they cover a wide variety of topics, ranging from the experimental psychology of visual perception, through specialized studies on Aristotle and the juridical intricacies of Austrian marital law, to extra-scientific pieces about chess and riddles. In view of this unusual situation, it seems clear that Brentano must have exerted his undoubted and far-reaching philosophical influence almost exclusively through his lecture courses. Through those courses he attracted many gifted students, and they constituted a school whose members came to hold important chairs not only in Austria, but also in Germany. Although these students, in their publications, often refer to Brentano's Psychology from an Empirical Standpoint published in 1874, they do so for the simple reason that his lecture courses were (and remained) unpublished and could not be quoted directly, and this was therefore the only published work which they could cite.