This essay offers an analysis of Paul Auster's novel Invisible. The main focus of the essay is on the incestuous love affair between Adam Walker and his sister Gwyn. It is argued that the novel via this incestuous affair is addressing the issue of the unrepresentable, what Lacan termed the “real” that lies beyond the symbolic order. It is shown that the concept of the unrepresentable has been a central theme in Auster's work throughout his career. The main theoretical foundation of the essay is Julia Kristeva's theories regarding the “abject.” A summary of Kristeva's theories is therefore offered, as well as a summary of research into the incest taboo.