This thesis is an attempt to understand the essential properties of concrete objects. The underlying motivation of this investigation is the hope that by understanding essential properties we will be in a better position to construct a satisfactory metaphysical account of the things that populate the world around us. The initial chapter introduces two questions that this thesis will attempt to answer. The first, ‘what are essential properties?’ is the Analysis Question. Answering it occupies chapters two through five. The second, ‘what essential properties are there?’ is the Extension Question. This is dealt with in the final three chapters. Chapter two provides the beginnings of an answer to the Analysis question, introducing the modal analysis of essential properties. Eight ways modality and essentiality might be related are raised. Of these, two entail the modal analysis. By eliminating the undesirable six, justification for the modal analysis could be provide. In the remainder of the chapter, five of the six are quickly dismissed. Chapter three is an examination of Fundamentalism. Focusing upon the views of E.J. Lowe and Kit Fine, I argue that there are modal facts which cannot be grounded upon essence facts and that certain modal concepts are employed in the construction of the Fundamentalist account. Consequently, Fundamentalism cannot succeed in grounding modality, and therefore cannot be the correct way to understand essentiality. This concludes the argument by elimination, thereby justifying accepting the modal analysis. Chapter four explores the modal analysis. After distinguishing between various formulations, it is argued that an existence-dependent version of the modal analysis is best. An objection by McLeod concerning contingent existence and essential properties is then dealt with, setting the stage for a more troubling objection from Kit Fine. Fine argues that all forms of the modal analysis ‘get the essential properties wrong’, relying upon a series of example properties, including the relation between Socrates and {Socrates}. After breaking down Fine’s argument, the remainder of the chapter concerns examining and dismissing several bad responses to Fine’s argument, including attempts by Della Rocca and Gorman. In chapter five I advance a new response to Fine which centres upon appealing to the sparse/abundant property distinction. Incorporating this distinction into the modal criteria, I demonstrate that a form of the modal analysis can avoid Fine’s attack. I then conclude that this suitably modified modal analysis is an excellent answer to the Analysis Question. The remaining three chapters are part of an attempt to answer the Extension Question. Chapter six critically examines Wiggins’ sortal essentialism, the position that objects are essentially instances of their sorts. After rendering Wiggins’ essentialist argument, I demonstrate that it is either inconclusive or question begging. As such, there is no reason to accept sortal essentialism. Chapter seven looks at the Byzantine arguments concerning origin essentialism. It is shown that these arguments are either inconclusive - in that they do not entail origin essentialism - or assume origin essentialism at the out-set, leaving us little reason to accept origin essentialism. Chapter eight examines Mackie’s minimalist essentialism. After laying out the position, I then examine a series of objections it faces. In particular, I show that even if we accept minimalist essentialism, it would not help us answer the Extension Question. As such, we have no reason to do so. I conclude that essential properties can best be understood as those sparse properties of an object which satisfy a specific modal criterion, as demonstrated in chapter five. However, the number of properties that satisfy this criterion might be quite small, as indicated by the results of chapters six through eight. This result is a mixed one for the essentialist: while we now know what essential properties are, it seems like we lost them all somewhere along the way.