Both history of science and philosophy of science have long genealogies as academic specialities. Philosophers of science generally trace their roots to Aristotle’s Posterior Analytics. That work – with its emphasis on the structure of explanation, the nature of causation and the linkage between concepts and experience – effectively paved the way for much of the subsequent development of the discipline. History of science is a comparative newcomer, usually seen as emerging from the pioneering studies of Priestley, Smith and Montucla in the late eighteenth century. Despite their quite divergent origins, each of these disciplines first came into its own during the nineteenth century. It was then, for instance, that philosophy of science began to assume an identity distinct from epistemology and when history of science came to be seen as more than an ancillary branch of the general history of learning.