There are a lot of metaphors you can use to describe a rock band and its members: they're an artistic collective, a corporation, a street gang. But one of the most enduring is this: a rock group is a family. And so it's no accident that rock & roll has plenty of musicians who are actually related by blood. It can be hard to swallow taking orders from your brother, even if he's a genius – that's why the most contentious rock bands are those with two brothers locking horns. As famous rock critic Leo Tolstoy observed, "Happy families are all alike; every unhappy family is unhappy in its own way."