Some writers have bum luck getting their books made into movies, let alone good ones. Dennis Lehane is not one of them. But the Dorchester native, whose novels “Mystic River,’’ “Gone, Baby, Gone,’’ and “Shutter Island’’ have all made it to the big screen with reasonably good results, says it’s not luck. Speaking at the Coolidge Corner Theatre this week, Lehane (above), whose new book, “Live by Night,’’ just came out, said he’s very careful in his dealings with Hollywood. “If you deal with a studio, it’s a bunch of people who don’t understand your work, who hire a bunch of people who don’t understand your work, who hire a writer to write a script that sucks,’’ said Lehane. In the case of “Mystic River,’’ he dealt with Clint Eastwood, who consulted with Lehane on casting. Well, sort of. “He called me and was so sweet,’’ said Lehane. “He said, ‘Who were you thinking of for the character of Jimmy Markum?’ And I said, ‘Oh, I was thinking Russell Crowe.’ And he said, ‘I just hired Sean Penn.’ I was, like, ‘Well, Sean’s good.’ And then he said, ‘What about for Dave Boyle?’ And I said, ‘I really like this guy Liev Schreiber.’ And he said, ‘I don’t know who that is so I got Tim Robbins.’ It just went down the list like that. It was really sweet, but it was, like, ‘Why are you asking me?’ ’’ . . . Coincidentally, at the very moment Lehane was talking at the Coolidge, Schreiber was grabbing a lobster roll to go at LTK at Logan.