This project presents a principled and systematic approach to how to understand natural modality taking powers as an ontological (and modal) primitive. The project is divided in two main parts.In the first part of the dissertation, I identify the aspects of scientific practice that bear on our understanding of natural possibility and necessity. Then, I argue that attention to scientific practice suggests that laws of nature are not the only relevant source of information about what scientific theories tell us about natural modality. Rather, I argue that, in order to do justice to the variety and complexity of practices involving modal reasoning in science, we should take into account many other modal concepts such as those of dispositions and mechanisms.In the second part of the dissertation, I develop a scientifically informed conceptual framework that systematically accounts for the information about what is naturally possible encoded in a wide variety of modal concepts including laws of nature, but also dispositions and mechanisms. This conceptual framework takes dispositional properties (also known as `powers') as modally and explanatorily primitive in order to provide a systematic account of the modal features of dispositions, mechanisms, and laws of nature. The resulting conceptual framework allows us to (i) accommodate a wide range of natural necessities, including natural necessities with different scopes, degrees of generality and strictness, as well as natural necessities with different degrees of modal force; (ii) systematically account for the variety of natural possibilities we find in scientific practice; and (iii) provide truth conditions for counterfactual conditionals regarding natural modality.