The work of Spinoza, Descartes and Leibniz is cited in an attempt to develop, both expositorily and critically, the philosophy of Anne Viscountess Conway. Broadly, it is contended that Conway's metaphysics, epistemology and account of the passions not only bear intriguing comparison with the work of the other well-known rationalists, but supersede them in some ways, particularly insofar as the notions of substance and ontological hierarchy are concerned. Citing the commentary of Loptson and Carolyn Merchant, and alluding to other commentary on the Cambridge Platonists whose work was done in tandem with Conway's, it is contended that Conway's conception of the “monad” preceded and influenced Leibniz's, and that her monistic vitalism was in many respects a superior metaphysics to the Cartesian system. It is concluded that we owe Conway more attention and celebration than she has thus far received.