Just when you think that every rare recording ever made must have been unearthed by now, along comes something like this trove of blues obscurities by such giants of the genre as Charley Patton, Leadbelly, Big Bill Broonzy and the Rev. Gary Davis (as well as a few lesser-knowns). The ancient recordings—many of them earache-inducing scratch-fests despite the best modern cleanup efforts—span the three-decade period of 192656 and, as such, offer a glimpse into the world of African-American culture during a time of great flux, when segregation was still very much taken for granted and blues music provided a means of expression within a closed-off community. Back-to-back versions on the “Poor Boy” theme, first by Gus Cannon and Blind Blake and next by Ramblin’ Willard Thomas, expound on hopes of survival and escape, and Broonzy’s “Starvation Blues” is self-explanatory. All is not forlorn though: the ubiquitous risqué entendres suggest that there’s always more than one way to have a good time, and when all else fails, leave it to Leadbelly to wax eloquently on the merits of the pancake.