Brothers J.E. and Wade Mainer and their various bands and configurations formed a kind of bridge between the Appalachian string bands of the 1920s and the high-powered bluegrass bands that emerged after World War II. This 100-track box set from JSP is the second box the label has issued charting the early years of this oftentimes dueling and quarreling pair in their various guises, sometimes together, sometimes not, and, more often than not, working with guitarist Zeke Morris as the Mountaineers, the Dixie Reelers, or the Morris Brothers. This installment covers the years 1937 to 1941 and features tracks cut as the Mountaineers and the Smilin’ Rangers, among others, with the usual associates, including J.E. Mainer, Wade Mainer, Zeke Morris, and ace fiddler Steve Ledford.