In 1991 Gass became a visiting scholar at the Getty Institute in order to finish the novel, and Knopf published The Tunnel in 1995. It is the story of a middle-aged professor who, upon completion of his massive historical study on Nazi Germany, finds himself writing a book about his own life instead of the introduction to his magnum opus. The Tunnel sharply divided critics upon its publication. It won the American Book Award, was a finalist for the Pen/Faulkner Award, and has seen numerous reprintings and foreign editions since its initial publication.

In 2005 Gass recorded an audiobook version of The Tunnel. The William H. Gass Papers include the master CD copies of this recording, spread out over 46 discs.

The layout and design instructions, as well as the typed outline notes, will be of particular interest to fans and scholars of The Tunnel. In these documents Gass explicates some of his original ideas for how the book should be presented, and the organizational scheme and thematic characteristics of the story. (Note: as with the outlines and notes for the other books included in this exhibit, these documents do not necessarily reflect the final text.)