This book is D. M. Armstrong's influential defense of his original theory of what a law of nature is.

First published in 1985, D. M. Armstrong's original work on what laws of nature are has continued to be influential in the areas of metaphysics and philosophy of science. Presenting a definitive attack on the sceptical Humean view, that laws are no more than a regularity of coincidence between stances of properties, Armstrong establishes his own theory and defends it concisely and systematically against objections. Presented in a fresh twenty-first-century series livery, and including a specially commissioned preface written by Marc Lange, illuminating its continuing importance and relevance to philosophical enquiry, this influential work is available for a new generation of readers.