In the introduction I identified two general tendencies in all of Deleuze's readings of Leibniz. I characterised these as the presence of ‘two Leibnizes’: on the one hand, the theologically conservative Leibniz, subject to Deleuze's relentless criticism; and on the other the philosophically adventurous Leibniz, a useful source of inspiration and influence. In a very general sense, the division between the main text and the conclusion of Expressionism in Philosophy: Spinoza (EPS) follows this distinction: the critical tone which dominates in the main text is replaced by admiration when we arrive at the conclusion. This distinction is not clear-cut, however, and we’ll often detect the more-or-less suppressed presence of both Leibnizes at each stage.

Along with their critical tone, there is one other important feature of the discussions of Leibniz we find in the main text of EPS: they are, we are forced to admit, incidental. Despite occasional references to an ‘anti-Cartesian reaction’ which unites Leibniz and Spinoza, we never get the sense that this is a central point of concern for Deleuze. It is a reading of Spinoza's philosophy through the concept of expression which motivates the text as a whole. Limited to this context, the affinities between Spinoza and Leibniz are, at best, a point of interest, and their differences are, at best, a useful point of opposition to better draw out Spinoza's originality. It is this which will change in the concluding chapter. There, it is precisely these apparently incidental affinities and oppositions between Spinoza and Leibniz that drive Deleuze's argument and become the central point of concern. The new emphasis on Leibniz will introduce, in nascent form, the Leibnizian ideas and concepts that Deleuze increasingly takes to heart in his later works.

EPS is Deleuze's most ‘scholarly’ book, carefully charting a comprehensive reading of Spinoza in terms of the concept of expression (and a particular perspective on that concept). While we must still concede what Beistegui calls ‘a degree of hermeneutic violence’ in Deleuze's reading of Spinoza, the book nevertheless lacks the agile leaps between philosophers and disciplines that will characterise so many of Deleuze's later books, especially Difference and Repetition and Logic of Sense (Beistegui 2010: 28).