A dude named Akiva Goldsman was responsible for translating Sylvia Nasar's biography of John Nash to the screen. Apparently, he wasn't super great at math, so it's ironic that he was tasked with writing a movie about one of the best mathematical minds ever. (Source)
Goldsman is a bit of a multi-talent, with credits in both screenwriting and producing—which is probably why he's worth about $50 million. His writing credits span a whole bunch of different types of movies, from adaptations of John Grisham novels such as The Client (1994) and A Time to Kill (1996), Dan Brown adaptations such as The Da Vinci Code (2006) and Angels and Demons (2009), the adaptation of Stephen King's The Dark Tower (2017), and so on. Hmm, it seems he has a particular flair for book to screen action, doesn't it?
In any case, it's an impressive resume. And, oh, as you may have noticed from that list, he really likes collaborating with director Ron Howard. We suppose if you have a winning (like, literally Oscar-winning) formula, you stick with it, right?