http://www.gq.com/story/encyclopedia-of-matt-damon

Martin Scorsese (director, ‘The Departed’): He comes from Boston; he's familiar with that world. When we were cutting The Departed, my editor, Thelma Schoonmaker, used a term to describe Matt's presence on-screen that's stayed with me: He's seated as an actor. He enters a movie grounded and at ease in his character and in the world of the story.

Ledger, Heath Gilliam: Matt is mathematical at times, and that's both a strength and sometimes… I think that's what it maybe was between him and Heath. Because [Heath's] heart was on his sleeve, and that opened up a lot in Matt. Damon: He was too bright for this world. Coming off [The Brothers Grimm, I was] telling everybody that I just worked with the best actor I've ever seen. And people were like, “What are you talking about? The guy from A Knight's Tale?” And I was like, “You just wait. And wait until you see what kind of a director he's gonna be.” There were things that he did where I couldn't have got there in three lifetimes. And there were ways in which he was like a puppy dog. You wanted to protect him. [His death was] just fucking pointless. I called Terry when I found out, and he was like, “I'm sitting here in Vancouver. I'm looking out the window, and it's a beautiful sunny day, and the lights are turning red, and the lights are turning green, and cars are stopping, and cars are driving. I am surrounded by mediocrity. And he's gone.”