 After his first marriage ended in divorce, in 1971 Salmon married Merrilee Ashby, herself a philosopher of science. In 1973 Salmon and his wife left Indiana and took positions at the University of Arizona, to stay there until 1981 when they both moved to the University of Pittsburgh. There, in 1983 Salmon was appointed University Professor at the Philosophy department as a successor of Carl Gustav Hempel, a position he held until his retirement in 1999. In Pittsburgh philosophy of science was flourishing, thanks to a large community belonging not only to the department of Philosophy, but also the department of History and Philosophy of Science, the Center for Philosophy of Science, and the Philosophy department of Carnegie Mellon University. As a member of such a lively philosophical community Salmon enjoyed a most congenial atmosphere for twenty extremely productive years, leading to the publication of the book Scientific Explanation and the Causal Structure of the World (1984), a milestone of the literature on scientific explanation and the apex of Salmon’s work on the topic, the collection, edited with Philip Kitcher, Scientific Explanation (1989), which included as a chapter the essay “Four Decades of Scientific Explanation”, to be published one year later as a book (1990a), and a long series of articles which later merged into the two collections Causality and Explanation (1998) and Reality and Rationality, edited by P. Dowe and M.H. Salmon, which appeared posthumously in 2005.