Perhaps the philosophical thesis most commonly associated with Brentano is that intentionality is the mark of the mental. But in fact Brentano often and centrally uses also what he calls "inner perception" to demarcate the mental. In this chapter, I offer a new interpretation of Brentano's conception of the interrelations among mentality, intentionality, and inner perception. According to this interpretation, Brentano took the concept of mind to be a natural-kind concept, with intentionality constituting the underlying nature of the mental and inner-perceivability serving as the concept's reference-fixer.