 The complex set of issues described in the preceding section two were all brought together in the work of Buffon. In a remarkable career transition in 1739 in which he moved from his position as a pensioned mathematician in the Paris Royal Academy of Sciences, to a royal appointment to the Directorship of the King’s Garden and Natural History Cabinet (Jardin du Roi) in Paris, Buffon brought with him to the domain of natural history and to his reflection on issues in biology his deep familiarity with the major theoretical debates dividing Newtonians, Cartesians, and Leibnizians in his era. He was also intimately acquainted through his friend Maupertuis with the debates over generation theory and theories of the earth. He fashioned these ingredients into a set of new perspectives that were to define his novel approach to the life sciences over the last half-century of the Bourbon monarchy. In the interpretation of this article, Buffon is the major figure to put together a set of issues that formed the pre-conditions for transformism in biology, although he would never himself move into this theoretical region. Through his immensely popular writings, which were translated into all major European languages, he exerted an influence on discussions that ranged from St. Petersburg in Russia to Virginia in the American colonies.