Part Five of Spinoza's "Ethics" includes a notoriously challenging set of propositions about human perfection. Part of the difficulty in interpreting these elements of the work arises from neglecting important philosophical background for the relevant propositions, namely, medieval Jewish rationalism and Maimonides in particular. Spinoza was well acquainted with Maimonides' "Guide of the Perplexted" as well as his halakhic or legal writings. For both Spinoza and Maimonides (who, in turn, is a good Aristotelian on this matter), human perfection is essentially a cognitive matter, albeit one with an affective component, whereby the highest good for a human being consists in the superb and joyful intellectual condition that is the knowledge and love of God. My goal in this essay, then, is to see whether any light can be thrown on Spinoza's views on this topic by considering them through a Maimonidean lens.