This edition aims to make Margaret Cavendish’s most mature philosophical work more accessible to students and scholars of the period. is important not only because it is Cavendish’s final articulation of her metaphysics but also because it succinctly outlines her fundamental views on “the nature of nature”—or the base substance and mechanics of all natural matter—and vividly demonstrates her probabilistic approach to philosophical enquiry. Moreover, spends considerable time discussing the human body, including the functions of the mind, a topic of growing interest to both historians of philosophy and literary scholars. This Broadview Edition opens to modern readers a vibrant, unique, and provocative voice of the past that challenges our standard view of seventeenth-century English philosophy.