Superfan is Letterman's unlikely archivist

New York

David Letterman is one of the greatest entertainers in the history of television, but his legacy is more fragile than you may think.

That's because the late night talk show is an ephemeral form, its hosts forgotten faster than teen idols. One-time superstars such as Steve Allen and Jack Paar have faded into obscurity, primarily because it's difficult to see their shows, and much of Johnny Carson's oeuvre was erased. Letterman's work is not so hard to find, thanks in large part to Don Giller, a superfan who stumbled into becoming a critical custodian of Letterman's comedy.