During the seventeenth century, disputes over middle knowledge centered on the following question: Does god know contingent states of affairs before he decrees to bring them about (the Jesuit view); or, conversely, does he know them after he has decreed which states of affairs he will bring about (the Dominican view)? This article intends to cast some light on Leibniz's view of this question. Of central importance here is the notion of a possible decree (designed both to ground contingency and to explain god's knowledge). Despite his apparent proximity to the Dominican view, Leibniz maintained the prevolitional nature of god's knowledge of contingent states of affairs. In order to establish this point, Leibniz's view is compared to some little known developments in the theory of middle knowledge.