John Milton, England's greatest narrative poet, and Isaac Newton, England's greatest natural philosopher, are rarely thought of together. While one is regarded as the last great figure of the English Renaissance and the other as the first great figure of the English Enlightenment, their lives overlapped for three decades, and their intellectual and social networks intersected. This book not only reveals surprising and arresting parallels between their vitalist speculations on the life of matter, their unorthodox views on the Christian godhead, and their self-understanding as prophets, but also demonstrates that their natural philosophical views are connected to their unusual and, from orthodox perspectives, heretical antitrinitarian Christian views. While Milton's and Newton's systems of thought parallel each other in sometimes uncanny ways, those systems diverge in ways dictated by their deepest commitments, Milton's to freedom of the will and Newton's to divine omnipotence. In a revision of Stephen M. Fallon's argument in Milton among the Philosophers that Milton's animist materialism was idiosyncratic, Milton emerges in this book as both a participant in a vigorous vitalist movement in experimental natural philosophy and an early adopter of key ideas that would characterize the Newton circle in the decades after the poet's death. This study casts light on the significance of Milton's thought and on his place in intellectual history, while at the same time situating less familiar aspects of Newton's work in that history. Readers will find that apparently fanciful elements of Milton's epic stage have solid contemporary natural philosophical foundations.