Family and Jimmie Rodgers form the foundation of the entire spectrum of country-music repertoires and performance styles. Though the two acts are often mentioned in the same breath today, record buyers of the late ’20s and early ’30s heard remarkable differences between the Carters’ stark ballads and sacred songs and the blue yodels of the Singing Brakeman. Sunshine in the Shadows: 1931-1932, Rounder’s fifth release in a projected series of nine CDs documenting the Carters’ complete recordings for the Victor label, includes such works as “Let the Church Roll On” (a future bluegrass gospel standard) and “Can’t Feel at Home” (which Woody Guthrie would later rework into “I Ain’t Got No Home”). While the disc does not contain any of the classics most closely associated with the Carter Family (“Wildwood Flower,” “Keep on the Sunny Side,” “Jimmy Brown the Newsboy”), it includes the only four sides the Carters cut with Rodgers. The ever-charismatic Rodgers replaces the ever-serious A.P., joining Sara on two duets, “Why There’s a Tear in My Eye” and “The Wonderful City,” accompanied by Maybelle’s guitar. The two remaining sides, “Jimmie Rodgers Visits the Carter Family” and “The Carter Family and Jimmie Rodgers in Texas,” are fascinating novelties reminiscent of radio skits of the era, although the scripts are downright awful and the acting is even worse. Better introductions to the music of the Carter Family and Rodgers exist, but this disc includes four tracks that will be deemed essential by country music historians and enthusiasts.