Much has been written recently about the Deleuzian concept of becoming. Most of that writing, especially in feminist criticism, has drawn from the later collaborations with Guattari. However, the concept of a becoming arises earlier and appears more consistently across the trajectory of Deleuze's work than the discussion of specific becomings might lead one to believe. In this paper, I trace the concept of becoming in Deleuze's work, and specifically in the earlier works. By doing so, I hope to shed some light on the specific becomings that are the focus of the collaborative work with Guattari, and to deepen an understanding of the concept in general.