My dissertation focuses on a central problem in early modern metaphysics: if God maintains creatures in existence by continually creating them, how can creatures be genuine productive causes? In the first part, I argue that despite his monism, Spinoza was concerned with a version of this problem, and that recognition of this concern motivates a new interpretation of Spinoza’s metaphysics of causation. In the second part, I show that Leibniz’s view of divine and secondary causation is not what previous commentators have taken it to be, and argue that a different interpretation accommodates Leibniz’s metaphysical and theological commitments more easily.