Barry Loewer presents a novel account of the metaphysics of law of nature, chances, fundamental ontology, and the space-time arena they occupy. He calls this the Package Deal Account. This aims to answer Stephen Hawking's question "What is it that breathes fire into the equations and makes a universe for them to describe?" Loewer's account stands on the shoulders of David Lewis's Humean Best Systems Account of laws and chances, but rejects Lewis' Humean ontology of natural properties, and instead lets the criteria that physicists employ for evaluating candidate fundamental theories of everything, together with reality, determine the universe's fundamental ontology. The Package Deal Account thus advances the project of naturalizing metaphysics.

Loewer discusses the history of the concept of laws of nature, current philosophical accounts of the metaphysics of laws, and arguments for and against each of these. He then shows how the Package Deal Account overcomes objections to each, and how, unlike Lewis's Humean account and its non-Humean rivals, it is able to accommodate recent developments in physics, including proposals for theories of quantum gravity that reject the fundamentality of space-time. Loewer provides in addition an account of the laws and chances that occur in non-fundamental special sciences and how they are related to those of fundamental physics.