Uncover the profound impact of “principles” in early modern thought with this groundbreaking interdisciplinary study. This collection offers the first sustained examination of principles, tracing their crucial role in the works of Newton and Leibniz, and across diverse fields like mathematics, law, and natural philosophy during the seventeenth century. Essential reading for students, researchers, and academics specialising in seventeenth-century philosophy, history of science, and intellectual history, this volume charts a central concept of the era and opens new avenues for scholarly inquiry.