Gilles Deleuze considered 'assemblage' theory to be his most significant contribution to philosophy. It is a complex and nuanced concept and one that is central to how Deleuze and Guattari constructed their theoretical work. In Assemblage Theory and Affect Ian Buchanan continues his project of demystifying this key theory and introducing its primary qualities. Buchanan argues that assemblage theory, as conceived by Deleuze and Guattari, is primarily about desire. And, further to that, there is no greater manifestation of desire than 'affect'. Indeed, in order to understand assemblage you also need to understand affect and vice versa.