This dissertation examines Heidegger's account of being (Sein) in Being and Time. It defends the straightforward but controversial thesis that Heidegger understands the being of entities as one of their properties. Since many analytic philosophers are suspicious of being-talk but perfectly comfortable with property-talk, this position provides a new opportunity for dialogue between analytic philosophers and Heideggerians. Once analytic philosophers are clear on which properties Heidegger is talking about, there can be constructive engagement between them and Heideggerians over whether or not entities--especially human beings--really have these properties.Heidegger divides the being of entities into two fundamental kinds: our kind of being, which he calls 'care' (Sorge), and the kinds of being possessed by every other kind of entity. I argue that the property Heidegger identifies with the being of entities other than us is their meaningfulness, i.e., the conjunction of their involvement, their intelligibility, and their significance. (Roughly, a thing's involvement is the way it is used or otherwise involved in some human activity; a thing's intelligibility is the way it makes sense to us; and a thing's significance is the way it matters to or has value for us.) Our kind of being, care, is just the flipside of this: care is the conjunction of engaging in human activities, finding things intelligible, and finding things significant. At the end of the dissertation I consider by what right Heidegger identifies these particular properties (i.e., meaningfulness and care) with the 'being' of entities. I distinguish between two concepts of being, a 'thin' concept and a 'thick' concept, and argue that Heidegger's account is an account of being in virtue of its connection to the latter, thick concept. This distinction explains why Heidegger scholars and analytic philosophers have not found each other's work on being more useful, for the former are concerned primarily with the thick concept of being, the latter with the thin concept. Nevertheless, since both concepts are legitimate, neither group has the right to dismiss the other on the grounds that it fundamentally misunderstands the nature of being.