It began in clubs, of course. The faces were closer to the stage back then, and during the breaks, there were the cigarettes and coffee, the warm beer and the instant feedback. It was the beginning of a long relationship between Paul McCartney and his audience, that group of fans who’ve followed him from the beginning, and found his music a powerful marker in their own lives. With “The Space Within US,” it becomes more obvious than ever. Paul McCartney has been feeling the same thing on his side of the relationship. “I relate to them,” he says in one of this film’s remarkably personal interviews, “It’s quite emotional for me … ”