Written in 1945 for the French flautist Rene le Roy this three movement sonata has as the motif for its last movement the song of a small bird called the whippoorwill. Martinu encountered this bird during the summer of 1945 which he spent in Cape Cod and it sang all night long during the entire summer!
Martinu was born and raised in rural Czechoslovakia but spent half of his life away from his homeland. He moved to Paris in the 1920's for artistic reasons and then to the USA to escape from Nazi occupied Europe. Although successful in America he never lost his love of his native country and although he didn't return directly after the war (due to the death of friends and his mother) he eventually left the USA in 1953.