“When You Are Lonely” was recorded by Bill Monroe and his Blue Grass Boys in 1948 for Columbia, the version associated with this entry. The recording belongs to the “classic” Blue Grass Boys lineup with Lester Flatt, Earl Scruggs, Chubby Wise, and Howard Watts (Cedric Rainwater) — the configuration that effectively defined the bluegrass sound during its 1946–1948 founding window.
The song’s authorship is generally given to Bill Monroe, in keeping with most of his Columbia-era writer-credited material. The lyric is a wry-yearning piece: the narrator’s former lover will eventually be lonely too, the singer suggests, and on that distant day she might finally understand what she lost. The conceit gives the song a quiet bitterness rather than the more straightforward heartbreak grief of pieces like “Toy Heart.”
Monroe’s high tenor lead carries the lyric’s controlled bitterness; Flatt’s flat-baritone underneath gives the chorus its weighty harmonic shape. Scruggs’s three-finger banjo break is one of the more frequently transcribed solos from the late-1940s session work. The song works as a moderate-tempo vocal piece in G with a clear chorus harmony slot, and it remains a regular call in Monroe-era traditional bluegrass jams.