The second volume of Bear Family's four-part Acoustic Blues series showcases the '40s and '50s, which were pivotal years in the maturation of recorded blues. What this collection skips by design is the rise of electric blues -- that's covered on Bear Family's companion 2012 series Electric Blues -- a movement that wound up pigeonholing purveyors of acoustic blues as purists, but during these two decades there still were emerging new bluesmen who had yet to plug into an amp. This generation included musicians that would later electrify -- Muddy Waters, Robert Lockwood, and Lowell Fulson, all featured here -- but there also were figures like Lightnin' Hopkins and Arthur "Big Boy" Crudup who would continue to play an acoustic. As this volume reaches its conclusion, the folk-blues revival of the '50s surfaces via Jesse Fuller, Big Bill Broonzy, and Mississippi Fred McDowell, but there's also the emergence of the titan John Lee Hooker, a man who would also later plug in but never lose the essence of the Delta. Still, what's best about this expertly assembled and annotated collection -- this, like the rest, is produced by Bill Dahl, who also wrote the liner notes -- is how it illustrates that acoustic blues remained vital in the '40s and '50s, that the musicians adapted to the time (listen to the jumping "Drinkin' Wine Spo-Dee-O-Dee" by Stick McGhee or the K.C. Douglas Trio's "Mercury Boogie," just one of many songs about cars), and that acoustic blues was not a thing of the past, it was still a music that spoke to how people lived their lives.