This is an analytic exposition of Brentano’s early theory of intentionality. The book is based in great part on the unpublished manuscripts where one can find substantially better articulated formulations then those expressed in the already published standard works. Its analysis concentrates mainly on the ontological and epistemological problems of Brentano’s immanent object. We highlight an interesting ambiguity of this concept and try to outline the inner logic of its evolution. It turns out that Brentano’s early philosophy of intentionality should be conceived not as a single, well defined theory but rather as a bundle of kindred but not always fully consistent and sometimes even competing ideas. Primary audience for the work are philosophers interested in Brentano’s philosophy, theory of intentionality and its epistemology and ontology, phenomenologists and cognitive scientists.