When Paul Giamatti talks about books—particularly the pulp fiction of his youth—his entire personality changes. He’s no longer the shy character actor soberly discussing his craft. He becomes a bundle of manic energy. He waves his arms around, his eyes wide as saucers, and laughs with such force that it seems he might burst. You half-expect him to pounce from his chair and come flying at you like some lit-geek equivalent of Gollum.

This enthusiasm is largely hidden in the Giamatti we’ve seen in the movies. In films like Sideways and Private Parts, he’s played mostly bitter and cantankerous schlubs, beaten down by despair and lacking any real joy. Brilliantly crafted characters, sure, but none of them very revealing of the off screen Giamatti. The closest he’s come to giving us a glimpse of the man behind the mask was 2003’s American Splendor, where he portrayed comic-book author (and avowed literary buff) Harvey Pekar. When Giamatti starts talking about cartoon superheroes and sci-fi paperbacks, it’s hard not to wonder if his performance in Splendor was, at least in part, a channeling of his inner fanboy.