It is an uncompromisingly dark work somewhat linked to medieval music, with influences from the tvísöngur tradition in a dissonant triadic context.
It contains three movements, with a short introduction and finale framing a much longer Passacaglia consisting in thirty variations.
Its theme comprises the total chromatic, critic Alex Ross described as Bach walking in the tundra.
[1] A performance of the work in March 1941 in the Sing-Akademie zu Berlin caused a scandal, with only twenty spectators remaining in the hall by the end and critic Fritz Stege condemning Leifs' "agonizingly narrow-minded intellectual world".
[2] The concerto is scored for solo organ, piccolo, flute, oboe, cor anglais, clarinet, bass clarinet, bassoon, contrabassoon, 2 horns, 2 trumpets, trombone, tuba, timpani, bass drum, cymbals, tam-tam, large woodblock/hammer, snare drum, triangle (3 percussion players required) and strings.