This two-disc, 25-track collection ostensibly celebrates Farm Aid's 15th anniversary. However, considering that this annual concert for the family-owned farm seems to play in smaller and smaller venues each year, it's also clear that the set is its own sort of fundraiser. As a satiric headline in The Onion recently proclaimed: "'Farm Aid' Aid Concert to Benefit Struggling 'Farm Aid' Concerts." At least the selections here, all recorded during Farm Aid shows between 1990 and '99, need little in the way of assistance. Willie Nelson and the Highwaymen work up a surprising head of steam for one more trip down to that "City of New Orleans." Farm Aid cofounders Neil Young (on "Homegrown") and John Mellencamp ("Rain on the Scarecrow") twang the rock and rock the twang, respectively, with intense and relevant performances. Keb' Mo', Los Lobos, Dwight Yoakam, Steve Earle, Bonnie Raitt, Bryan Adams, Beck (picking Jimmie Rodgers' peaches with Nelson), and a half dozen or so others offer impressive live performances, typically of their best-known work. In fact, if only the collection hadn't omitted every one of the No Depression acts (Wilco, Bottle Rockets, etc.) to have played Farm Aid over the years, Volume 1 might serve as a definitive sampler of American roots rock in all its permutations. With that end in mind, even the adolescent melodrama of the Dave Matthews Band and Susan Tedeschi's uncanny impersonation of a braying mule serve a representative purpose.