Three names dominate the trade in philosophy books in the period 1695–1830: John Locke, David Hume and Dugald Stewart. The triad familiar to undergraduates of Locke, Berkeley and Hume simply disappears when one considers the presence of their names on title pages up to the end of the eighteenth century: 229 times for Locke, 177 for Hume (including his History of England) and 55 for Berkeley. Locke’s works provide an important exemplar for the historiography of philosophy, though not necessarily for the publishing of philosophy in the eighteenth century, while those of Dugald Stewart represent a transition from recondite inquiry to university textbook. Locke, Hume and Stewart were frequently reprinted in the nineteenth century, and in the case of Locke and Hume no end seems in sight.

Eighteenth-century publishers and readers had less restricted ideas about what constituted a philosophy book than philosophy departments in universities have at the beginning of the twenty-first century. In the eighteenth century, it is reasonably safe to say that a book is a philosophy book if its author thought it was philosophical, or if it had the words ‘philosophy’ or ‘philosophical’ in its title (surprisingly few of the best-known ones do), or if its topics are epistemology, or morality, or aesthetics, or theology with epistemological or moral overtones, suppositions or conditions. Many eighteenth-century readers would have regarded Alexander Pope’s Essay on man (1733–4) and William Kenrick’s Epistles to Lorenzo (1756) as philosophical, and they were intended as such by their authors, although they are written in verse.