Those who lived above or alongside a gangway expressed their dislike of trespassers in various ways — with a frown, or a menacing broom. Safe passage required knowing the local demography. Where was the old man who’d set a snarling dog on a kid as he emerged from a gangway and dashed for the alley fence? Where did the woman live who claimed to know your mother and promised to tell on you? Was there really a gangway where you’d find yourself staring down the barrel of a shotgun?