A central concern of metaphysicians of science is uncovering the metaphysical content of our best scientific theories. One method for uncovering this content is with the use of indispensability arguments. These arguments infer the existence of some entity or structure on the basis of its presence in the formulation of some theory. While promised as a general argumentative strategy, the literature on indispensability arguments is generally concerned with the question of whether numbers are indispensable to our best scientific theories. In this dissertation, I cash in on the promise that indispensability arguments are generalizable by examining whether composite objects are indispensable to our best scientific theories. The first half of the dissertation (Chapters 2, 3, and 4) examines this question head on. I argue that the extant arguments for the indispensability of composite objects are not convincing, but once we sharpen our definition of indispensability, we see that there are good reasons to think that composites are, indeed, indispensable to our best scientific theories. In the second half, I examine the idea that indispensability is a guide to ontology from the perspective of philosophy of language. In Chapter 5, I present a novel interpretation of Putnam's original indispensability argument, where I argue that he is using the logic of linguistic presupposition. In Chapter 6, I try to show that sometimes it is permissible to linguistically subtract one's ontological commitment to some indispensable entity.