The term conversion carries connotations of religion and coloniality. But this has not prevented it from appearing, more generally, as an index of change and transformation. Barber – by drawing on debates in Religious Studies, Philosophy, Black Studies, and Media Studies – argues that conversion’s apparent generalizability is actually limited by its specifically Christian formation. Conversion names a specifically Christian operation that has itself converted to a generalizable form. Whereas conversion once mediated Christian salvation to the world, it now makes the world itself a secular medium of salvation. In this sense, conversion names a process that is both fluid and fixed, one that is capable of simultaneously sedimenting, exhausting, and generating identity. Within this process, exhaustion emerges both as a limit and as a new medium for production: by marking what threatens to be lost, it also names a condition from which we are supposed to be saved. Exhaustion, far from pointing to the cessation of the world, provides media for the world’s conversion. Against this ceaseless world – whether Christian, secular, or even post-secular – Barber proposes a logic of excommunication. This is a logic not of the “post-” but of the “non-,” not of new but of the never.