"As a key member of Bill MonroeÑ?s Blue Grass Boys in the 1940s, and then as partner to Earl Scruggs from 1948 to 1969, Lester Flatt helped shape and popularize bluegrass music. His warm vocals and solid rhythm playing were closely associated with this 1950 Martin D-28 guitar, customized with an enlarged pickguard, pearl inlays, and his name on the fretbaord. After Flatt purchased the instrument in 1956 from a West Virginia pawnshop, he used it on most Flatt & Scruggs recordings and performances.,For Flatt sideman Marty Stuart described the guitar with its full, rich tone, as "possibly one of the greatest rhythm instruments ever made," and Stuart used it extensively in his own solo career. Luthier Mike Longworth worked on the guitar for Flatt in 1956, adding the "L-5" pearl inlay at the seventeenth fret (Longworth, job # 5) and gluing his business card inside the sound hole."