Jon Marcus wrote the book on Boston secrets. No, seriously. It’s called Unknown New England, and it’s among eight titles he has authored or coauthored, most about Boston and New England. Boston born and bred (and descended from a line of small-time Boston mobsters), Marcus is the former editor of Boston magazine and writes about New England and other topics for magazines including Conde Nast Traveler, Yankee, the Boston Globe magazine and websites including concierge.com. He teaches at Boston College and Boston University.