Looking back, it makes sense that nobody could agree on what Bon Iver's second album was called. Was it simply "Bon Iver," as some, including the Grammy Awards, referred to it? Or was it the more complicated "Bon Iver, Bon Iver," as many of the record's rave reviews had it? The lack of consensus five years ago reflected a growing uncertainty about Bon Iver's identity -- a mystery that only intensifies with Friday's release of an excellent new album "22, a Million." The answer seemed plain enough in 2008, when the first Bon Iver album appeared, a stark yet tender document titled "For Emma, Forever Ago" that singer-songwriter Justin Vernon created largely by himself in a remote hunting cabin in the Wisconsin woods.