The Great Depression — which spanned roughly eleven years, from 1929 to 1940 — was the defining event of the generation of musicians whose music is documented on this nicely presented three-CD set. Tom Waits supplies a dark introduction, and the enclosed booklet is crammed with remarkable photos, but the music is even more surprising. The record biz was in its infancy, and labels recorded everybody, regardless of race or ethnicity, provided they could play well and sing at least competently. These recordings are mostly country, blues, and the proto-bluegrass known today as old-time music. The subject matter is grisly — train wrecks, plane crashes, floods, and industrial accidents as well as gory murders. Hits like “Frankie and Johnny” crop up, but most of the songs, and an ample portion of the players will be unknown to anyone who isn’t an old-time music aficionado. Cantor Joseph Rosenblatt intones “El Mole Rachmim fur Titanic.” Bob Miller delivers “Ohio Prison Fire” in an understated high tenor that contrasts with an over-the-top recitation of a mother weeping over her son’s “charred remains,” while Bill Cox sings “The Trial of Bruno Hauptmann,” a comprehensive description of the Lindbergh kidnap trial as detailed as an episode of Law and Order. The music, culled from 78 rpm recordings, was remastered to preserve its primal, mournful energy.