In this paper, I offer an account of the conceptual shift that occurs between the work completed by Gilles Deleuze prior to 1969 and his later work with Félix Guattari, beginning in 1972 with Anti-Oedipus. Against previous interpretations, which have concentrated on the developments initiated by Deleuze, I argue for the primary importance of Guattari's influence, especially his insistence on a theory of “machinic processes.” The importance of these processes is made manifest in Deleuze and Guattari's move away from theories (...) of structuralism. In order to carry out this task, I offer a close reading of Guattari's essay “Machine and Structure.” This essay was first written as a review of Deleuze's acclaimed work in Difference and Repetition and Logic of Sense and formed the basis for Deleuze and Guattari's first meeting. In the concluding sections of the paper, I show how the integration of the concept of the machine allows Deleuze and Guattari to develop a theory of the unconscious that operates outside of the boundaries traditionally set by structuralist analysis. (shrink)