Originally released in 1952, Harry Smith's landmark three-volume Anthology of American Folk Music literally instigated a revolution in music--suddenly, this collection of scratchy 78 sides made "folk" cool again (it would stay that way forever after). But Smith--filmmaker, guru, and alchemist--originally intended for a fourth volume of the set to be created. Thanks to Revenant, we have it now--nearly five decades after its gathering. Smith's two-CD collection takes works from the Blue Sky Boys, the Carter Family, Bukka White, Robert Johnson, and a dozen or so forgotten blues and old-time artists, mostly from the '20s and '30s. In the copious liner notes, the late Smith confesses that this volume was "lost" because his original liner notes went missing; he had hoped to create a thorough analysis of how each song's theme was interrelated. Thus, there are some truly great transitions--"John Henry Was a Little Boy" by J.E. Mainer's Mountaineers leads ironically into "Nine Pound Hammer Is Too Heavy" by the Monroe Brothers; Lead Belly's breakup ode "Packin' Trunk" segues into Big Joe Williams's "Baby Please Don't Go." Gorgeous packaging and thorough liner notes by Dick Spottswood, Greil Marcus, Ed Sanders, and others makes this set even more essential. Like so many of the musicians he admired and promoted, Harry Smith's real genius wouldn't be recognized till after he died. Here it is, folks. --Jason Verlinde