My current research focuses on the notion of grounding. The grounding relation is usually understood as a particular species of dependence – the way in which one thing may be said to depend on another for its existence and nature. Ideas about grounding are closely connected to the view that entities can be more or less fundamental, where the absolutely fundamental entities are generally thought to be those that do not depend on anything else. In my thesis I challenge standard conceptions of grounding and fundamentality. I am particularly interested in the way in which fundamentality, and especially grounding, is related to explanation. I argue that some of the ways in which notions of fundamentality are metaphysically and epistemically problematic can be resolved by taking seriously the idea that grounding is an explanatory notion, and explore the consequences for metaphysics concerned with grounding and fundamentality.