Focusing on the tropology of the monster within the writings of Charles Darwin and Jacques Derrida, this essay demonstrates certain significant linkages joining Darwinism to deconstruction. The monstrous relations between Darwin and Derrida--both genealogical and intertextual--reveal themselves in shared evolutionary-deconstructive approaches to the concept of species, the metaphor of the book of nature, and the mythology of the Garden of Eden. Challenging humanist metaphysics, Darwin and Derrida together advance a theoretical discourse attentive to the mutations, the perversions, the aberrations and the monstrosities of the world: a teratology that looks beyond man and humanism and towards the unknown posthuman future.