The Gibson Brothers' new album, Mockingbird, is a project 20 years in the making. The celebrated bluegrass duo-named back-to-back Entertainers of the Year by the International Bluegrass Music Association in 2012 and 2013-played the Nashville game two decades ago and were offered a major label deal, only to be told at the last minute that they were too "retro" for modern country music. Today, such a tag, along with "authentic" and "outlaw," is a buzzword, and all three can describe the marvelous Mockingbird. A mix of smooth country and Seventies rock, the album further cements the sibling duo of Leigh and Eric Gibson-still only in their 40s-as musical trailblazers. As players and vocalists, they are superb, harmonizing as only siblings can; while as songwriters they stand without peer, honored as Songwriters of the Year by the two leading bluegrass organizations. The 10 tracks on Mockingbird, their 14th album, draw on much of the brothers' experiences being raised in upstate New York, where they still reside on their family's farm.