A preliminary census of copies of the first edition of Newton's (1687).

When Henry Macomber published his census of owners of the first edition of the in 1953, he believed the edition to be small, 'perhaps not more than 250 copies', an estimate that still enjoys currency. Lower estimates of the size of the first edition of the were based partly on assessments regarding an inhospitable market for highly technical mathematical books, and partly on the presumption that the vaunted incomprehensibility of the would have militated against a sizeable edition. Our preliminary census more than doubles the number of identified copies, to 387-suggesting a much larger print run than commonly assumed - as well as encourages us to believe that there existed a wider, and competent, readership of the from the start. The long-standing assumption regarding the recondite nature of Newton's science as presented in the , together with claims concerning the scarcity of the book, brought many scholars to assume that Newton's masterpiece exerted little influence before the 1730s. The new empirical evidence presented in our census enables a reassessment of the early diffusion of the in Europe which, in turn, would necessitate a major refinement of our understanding of the contribution of Newtonianism to Enlightenment science.