PARK CITY, UT: We may not see a film at this year’s Sundance Film Festival that gets its key casting as right as James Ponsoldt’s The End of the Tour does. Based on Although Of Course You End Up Becoming Yourself, David Lipsky’s chronicle of five days spent with David Foster Wallace as he was becoming a literary superstar, the picture stars Jesse Eisenberg as Lipsky and Jason Segel as Wallace. Both are working familiar grooves: Segel is the shambling, likable, aw-shucks guy plagued with uncertainty, Eisenberg the seemingly cocky yet clearly brittle smart guy with the chip on his shoulder. To say that they’re working within familiar types is not to diminish their work here; if anything, they push their screen personas into new territory, while Ponsoldt tries (and mostly succeeds) to capture something of the Wallace mythos.

The opening passages are a bit unsteady; they provoke something akin to the response you might’ve had to those on-set photos that leaked a while back, where something about seeing Segal’s familiar form donning Wallace’s long hair and bandana was just a little jarring. But the more time Segel spends on screen, the easier it becomes to buy him in the role; he often plays characters who don’t quite seem comfortable in their own skin, and Wallace is much the same way. He’s perpetually apologizing and pre-apologizing (“Don’t expect any fireworks”), undercutting, covering, worrying. He’s uncomfortable about being interviewed, and about what it says about him that he’s becoming famous enough to be interviewed.

Lipsky still has the tapes that he made on that five-day journey, and Segel had access to them while crafting the performance. He also told me, at the Q&A following its Sundance premiere Friday night, “I read, and I read, and I read. I started a book club in the little town that I live in, with three really great book dorks who’ve read Infinite Jest like five times, and we talked through it… I think that one of the things about David Foster Wallace, that was so special about his writing, was that he touches on some very universal human feelings. So I tried to really pay attention to the parts of us that are the same.”

And while the film will certainly be of interest to Wallace superfans and other “book dorks” (“I say ‘book dorks’ with such love, you know,” Segel noted), there is much of it that’s not specific, that is more about those “universal human feelings.” David and “Dave,” the two writers, one on the rise and one still struggling, spend a good deal of time circling each other and sniffing each other out; there are few things on their earth more awkward that introverted writers interacting. They develop a rapport eventually, in fits and starts, though it seems to get tense whenever the tape recorder is brought out or mentioned, as though the exposing the construct of conversation immediately renders it false.

But it is very good conversation, and there’s a lot of it—in fact, I’m hard-pressed to think of a recent semi-mainstream film, aside from the Before series, with such an interest in the rhythms and give-and-take of conversation between two smart people (each trying to impress the other, even). And when things get sticky between them, the talk gets trickier; when they have a loaded conversation about Wallace’s “regular guy-ness,” they’re both so eloquent and so bristlingly intelligent and yet so clearly hypersensitive, you’re hard-pressed to figure out who’s actually “right” or “wrong.”

Because much of the film is two people in a single place talking, it’s perhaps a bit surprising that the screenwriter, Pulitzer Prize-winning playwright Donald Margulies, chose to adapt Lipsky’s book for the screen rather than the stage. “I felt that writing this as a two-hander would not do it justice,” he explained after the premiere. “I was very compelled by the idea of placing David Foster Wallace, one of the great chroniclers of American culture, on the American landscape. I thought that was a thrilling idea. The fact that he’s in a car on highways, and stopping for fast food, and going to the Mall of America, I thought, this is too fantastic.”

He’s right, but the film really comes together once they’re off the road, back in Wallace’s house in Indiana, where Segel has a pair of monologues about himself and his life that are keenly felt, intelligently delivered, and rather extraordinary. By the time we’re at the end of The End of the Tour, it’s arrived at something thoughtful and true about being a writer—and, even better, about being a real person.

The End of the Tour plays this week at the Sundance Film Festival.