Thomas Y. Crowell Company published in January, 1977 (although the copyright date is 1976) a book by Kristin Baggelaar and Donald Milton titled Folk Music, More Than a Song (340 entries, 110 illustrations, "hundreds of exclusive interviews and colorful, personal anecdotes"). Heavily slanted toward the revival singers, of course, it did include brief biographies of a number of traditional singers (Almeda Riddle, Sarah Ogan Gunning, Frank Proffitt, Dillard Chandler, Bascom Lunsford, Mance Lipscomb, Roscoe Holcomb, Buell Kazee, Ola Belle Reed, etc.), together with some of the collectors and scholars. You can skim through the essays about Linda Ronstadt or the Tarriers, if they're not your thing, to read about John A. Lomax and Kenny Goldstein or Paul Robeson and Jimmie Rodgers. Not a profound book, but worth looking for in the used book shops.

Sandy