Gottfried Wilhelm Leibniz (1646-1716) and Immanuel Kant (1724-1804) were the two most important figures in eighteenth-century German philosophy - indeed, they were two of the most important figures in the seventeenth and eighteenth centuries in general. Kant presents his philosophy as being important and revolutionary, in part at least, because of his particular rejection of the philosophy of Leibniz and the Leibnizian tradition of philosophy. Understanding how exactly Kant understood Leibniz and examining his arguments against Leibniz therefore leads us to a deeper understanding of the history of philosophy.