Jerry Lewis once blessed a nightclub audience by wishing them a life full of show business friends. Rob Long isn’t so sure that’s a blessing — show business friendship is a strange, contingent thing, built on projects that assemble and dissolve, sofas shared for a month, congratulatory phone calls that get read as job applications. This week: an awkward call to a not-quite-friend about her pilot, a rich old acquaintance unsettled by seminary news and a British actor stuck in contract purgatory at a long-ago dinner party who turned out fine. A theory of friendship, tested against thirty years of overlapping crews.