When approaching the philosophy of Deleuze in general, and the theory of imperceptible becomings (becoming(s)-imperceptible) in particular, as I am about to do, you must never underestimate the main idea that has been guiding Deleuze from Logique du sens to Critique et clinique. It is the idea that in any de facto event, empirically ascertainable, from the smallest to the largest (amorous encounter, historical event, revolution . . .), there is a part that cannot be effectuated, which constitutes its Sense, and which is the Event proper. In all accomplishing there is an inaccomplished, which is its better part, that which must be preserved. Such an idea, which implies an ontology of the virtual, brings into play a principle that opposes itself to the principle of determinism and of sufficient reason (the principium grande, as Leibniz calls it), principles which, for classical philosophy, rule all causal, physical, biological and social series. We shall name this opposed principle the principle of indetermination. The guiding idea of my intervention today is that in order to advance in the understanding of imperceptible becomings (becoming(s)imperceptible), we must cross the different authors that Melville, Masoch, La Fayette and Chretien de Troyes are. Bartleby reveals the principle of indetermination in its own capacity or power, which will be common to all the other characters, as the capacity of indiscernibility. Courtly love develops its unfinishedness, and the Princess of Cleves its unaccomplishedness. As for masochism, it reveals its power of suspension.