Stung by the allegation that his version of the new philosophy tended towards atheism and materialism, Sir William Petty – medic, mathematician, pioneering political economist, intellectual entrepreneur, and Fellow of the Royal Society – set out to compose a treatise vindicating his philosophical piety. Written between 1676 and 1678, this was entitled Of the Scale of Creatures. By redefining the scala naturae (“scale of creatures” or “chain of being”), Petty sought within it to combine doctrinal orthodoxy, biological comparativism, and a view of the world more familiar from the writings of Thomas Hobbes. Until recently, the Scale was thought only to survive in a partial copy within Petty’s own archive. William Petty on the Order of Nature provides a scholarly edition of the fullest version of the text, and in an introductory study assesses the Scale in relation both to Petty’s own thought and to the religious, philosophical, political, and literary dynamics of the later seventeenth century. Viewed through these prisms, Petty emerges as a thinker at striking ease in both ancient and modern traditions of learning. Further, early modern attitudes to the interactions between human and animal life are cast into revealing new relief, as are the histories of fields as diverse as theology, colonialism, anthropology (especially in connection with “racism” and the problem of human diversity), scribal culture, and political theory. In addition to those researching the cultural and intellectual contours of seventeenth-century natural philosophy, this book will be of interest to all scholars of early modern intellectual, religious, literary, and cultural history.