David (D. M.) Armstrong is one of Australia's greatest philosophers. His chief philosophical achievement has been the development of a core metaphysical programme, embracing the topics of universals, laws, modality and facts: a naturalistic metaphysics, consistent with a scientific view of the natural world. It is primarily through his work that Australian philosophy, and Australian metaphysics in particular, enjoys such a high reputation in the rest of the world. In this book Stephen Mumford offers an introduction to the full range of Armstrong's thought. Although Armstong's is a body of work that Mumford regards highly and of real significance, he nevertheless highlights areas of weakness and issues about which there is room for further debate.