Nantucket-based historian Nathaniel Philbrick, author of “Bunker Hill: A City, a Siege, a Revolution,” kicked off his book tour on Wednesday night with a Brookline Booksmith reading at the Coolidge Corner Theatre. Philbrick chatted with us just before the event and said he’s thrilled that a “Bunker Hill” movie based on his book is already in development. Ben Affleck and Warner Bros. secured the rights to the property last month. Philbrick said he doesn’t have any opinions about which actors should play the historical characters in his book (“I’m really bad with names,” he admitted), but he said he is a big fan of the movies, in general. When he got to Boston on Tuesday night, he took himself to see Tom Cruise’s “Oblivion.” (“It was good,” Philbrick reports.) If Affleck does decide to cast himself in the “Bunker Hill” project, we vote that he plays John Hancock. Philbrick describes Hancock in the book as a 37-year-old “uncrowned king.” “Handsome, with the stubble of a beard on his clean-shaven cheeks . . .” Sounds like Ben, right?