Chuck Berry, besides all of his other notable achievements, wrote the unifying mission statement of rock’n’roll. Or as close to one as anyone’s ever gotten. He announced the arrival of a new culture, a new generational movement. I hate it when writers resort to those awful words, but, really, he “Changed The World Forever.” (Duh-duh-duh-DUHM!) Popular music and culture have mutated into unrecognizable shapes since Chuck Berry’s day, but the purpose of youth culture is still to shake off the old status quo. The spirit of making the old guard roll over in their graves doesn’t change with the generations. Chuck Berry himself is in his grave now, and he may well be tossing and turning over what the A$AP crew’s up to. But I’d like to think he’s at least getting a little chuckle, looking back at his legacy and the culture he helped create.