Bas van Fraassen's anti-realist account of science has played a major role in shaping recent philosophy of science. His constructive empiricism, in particular, has been widely discussed and criticized in the journal literature and is a standard topic in philosophy of science course curricula. Other aspects of his empiricism are less well known, including his empiricist account of scientific laws, his relatively recent re-evaluation of what it is to be an empiricist, and his empiricist structuralism. This essay attempts to provide (...) an overview of these diverse aspects of van Fraassen's empiricism and to show how they relate to one another. It also focuses on the nature of van Fraassens's epistemic voluntarism and its relationship to his empiricist philosophy of science. (shrink)