In October, John Ashbery became the first poet to be honored with a volume of his works in the Library of America series during his own lifetime. That honor says a number of things about the state of contemporary poetry — some good, some not so good — but perhaps the most important and disturbing question it raises is this: What will we do when Ashbery and his generation are gone? Because for the first time since the early 19th century, American poetry may be about to run out of greatness.