We're joined now by David Epstein, a former senior writer for Sports Illustrated who's just been hired by Pro Publica to be an investigative reporter. Epstein is the author of The Sports Gene: Inside the Science of Extraordinary Athletic Performance, which was recently published by Current. Among other things, the book refutes the 10,000-hours rule, made popular by Malcolm Gladwell, as an oversimplification. Have a question for Epstein? You may fire when ready down in the discussion.

Update (4:31 p.m.): Epstein's gotta run. We thank him for joining us, and thanks to all who submitted questions.