My title raises two questions, each of which I would like to address in turn. What is an immanent ethics (as opposed to an ethics that appeals to transcendence, or to universals). And what is the philosophical question of desire? My ultimate question concerns the link between these two issues: What relation does an immanent ethics have to the problem of desire? Historically, the first question is primarily linked with the names of Spinoza and Nietzsche (as well as, as we shall see, Leibniz), since it was Spinoza and Nietzsche who posed the question of an immanent ethics in its most rigorous form. The second question is linked to names like Freud and Lacan (and behind them, to Kant), since it was they who formulated the modern conceptualization of desire in its most acute form – that is, in terms of unconscious desire, desire as unconscious. It was in Anti-Oedipus, published in 1972, that Deleuze (along with Félix Guattari, his co-author) attempted to formulate his own theory of desire – what he would call a purely immanent theory of desire. In his preface to Anti-Oedipus, Michel Foucault claimed, famously, that “Anti-Oedipus is a book of ethics, the first book of ethics to be written in France in quite a long time” (Foucault 1977: xiii) – thereby making explicit the link between the theory of desire developed in Anti-Oedipus and the immanent theory of ethics Deleuze worked out in his monographs on Nietzsche and Spinoza.