This dissertation revisits the question of "who comes after the subject?" posed by JeanLuc Nancy in 1986. Assuming a position commensurate with the radical horizon of Nancy's challenge, this dissertation responds with the reject. Through close, "deconstructive" readings of Nancy, Derrida, Deleuze, Cixous, and Badiou, Towards a Theory of the Reject demonstrates that the reject has in fact always been at issue in "post-structuralist" philosophy. In the first section, I show how the reject not only posits a future relation beyond all current understandings of friendship, love, and community, but also offers a critique of today's garrulous network-centric sociality. The second section elucidates how the reject is at the heart of contemporary French thought's "deconstruction" of both sacred and secular worlds. In the third section, I articulate the political potentiality of the reject as a radical critique of existing "democratic" practices. Through these three sections, I also suggest that the reject responds to current "postsecular" endeavors to make faith and knowledge coexist, as well as to "posthuman" investments in the animal question and systems theory. The reject, moreover, can have ethical and political import for "post-secular" and "posthuman" futures. In general, this dissertation goes against the grain of resurrections of the subject in recent intellectual discourses, and argues that theorizing the reject, a figure not as yet explicitly formulated, while nonetheless a condition that almost all of us irreducibly experience in some ways at one time or another, can open up possibilities of another ethics and politics. Attempting to avoid the frequent reliance of earlier intellectual endeavors on the subject, whose assumed sovereign position only serves to negate the perspectives of others, Towards a Theory of the Reject shows that various approaches to ethics and politics can potentially and respectfully negotiate differences such that the articulation of one difference does not come at the expense of another.