Nicolas Malebranche's account of the nature of ideas and their role in knowledge and perception has been greatly misunderstood by both his critics and commentators. In this work, Nadler examines Malebranche's theory of ideas and the doctrine of the vision in God with the aim of replacing the standard interpretation of Malebranche's account with a new reading. He argues that Malebranche's ideas should be seen as essences or logical concepts, and that our apprehension of them is thus of a purely intellectual character and serves to provide us with knowledge of eternal truths. He then shows that the visionary representationalist reading usually given to Malebranche's theory of perception simply misconstrues the nature of ideas and the role he intended them to play in perception. Nadler's discussion includes detailed analyses of Malebranche's notion of representation and of his arguments for the presence of divine ideas in knowledge and perception. These aspects of Malebranche's system are considered both in light of his Cartesian and Augustinian commitments and in the broader seventeenth-century philosophical context.