It does, to be sure, take a certain strain of otherworldly brainpower to be a movie star in an era of microscopic tabloid scrutiny while somehow managing to keep your private life as trackless as a tabula rasa. In The Day the Earth Stood Still, a remake of the 1951 sci-fi movie, Keanu plays Klaatu. Klaatu is an alien who has inhabited a human body in order to mingle with mankind and figure out whether we deserve to be saved or wiped out. Keanu observes that "playing an alien is tough." Which is probably true, though if anyone's up to the task it's Keanu, the most extraterrestrial celebrity in our midst. "He's really still," says Emma Watts, the president of production at Fox, the studio that's putting out Earth. "He's got a stillness, and he's also a man of action." She remembers meeting with him to talk about the movie and noticing that he had jotted down three or four pages of exhaustive notes about the script. In very tiny handwriting.

The trailer for The Day the Earth Stood Still

So could it be? Is Keanu Reeves some kind of . . . stealth genius? "I've swapped a lot of books with him in the last nine months. He is one of the most voracious readers I've ever met," Derrickson says. "He's very unpretentious about it. Nobody really knows, and he doesn't really care that nobody knows." Nor does his reading come across as a glued-on Hollywood affectation—like a habit, say, of toting around a yellowed copy of Leaves of Grass in an attempt to look a few millimeters deeper than a smear of Kiehl's eye cream.

No. It becomes clear after 30 seconds of watching Keanu pinball around the aisles of Book Soup that he approaches the printed word as both a glutton and a gourmand: He inhales a lot, and he's game to order off-menu. He tells me he just finished all of the novels in John Updike's Rabbit series. "So fantastic," he says with a reverent hush. I mention another work about suburban crisis, Richard Yates' Revolutionary Road, and he rears back and slides the helmet onto his head so that he can free up his left hand. "Oh, YES!!!" he shouts. "Let's high-five on Revolutionary Road!" We slap palms. This prompts a rumination from Keanu on the primary characters in that book, Frank and April Wheeler, and "the identities that they're wearing—you know, their authentic self and then their external self and that dialogue that's going on."

As we pass Proust, Keanu reveals that he devoured every page of the meticulous colossus that is Remembrance of Things Past. "It took a couple of years, but I did it," he says. The grin has straightened itself; it's ear-to-ear now. "I didn't do the Moncrief, I did the newer translation. Some books would come in between. But I found that it was a thread—like time—that you could walk away and come back to. I didn't feel like I had lost the momentum of the story at all. It was like meeting a good friend or someone that you like, and you're like, 'Hey, dude! How's it goin'?'"