Duke Ellington’s signature composition was “Take the A Train,” written by his frequent collaborator Billy Strayhorn. The title refers to directions sent to Strayhorn by Ellington on how to reach his house via the subway trains running from Brooklyn to Harlem and onto Manhattan. The song brought Ellington and his band financial success, became his “theme” song that he would perform regularly for the rest of his life, and is still one of the most important compositions in all of jazz. The pair met in 1938, and the very next year Strayhorn composed “A Train.” Strayhorn had an uncanny ability to emulate Ellington’s style while infusing it with a melody and lyricism that resembled the emerging “swing” genre. Music historians attribute Ellington’s rebounding success in the 1940s to the help of Strayhorn. Duke Ellington composed many songs independently of Billy Strayhorn, including "Mood Indigo," "In a Sentimental Mood," "Solitude," "Satin Doll," and "Sophisticated Lady". While Strayhorn is known for composing the Duke Ellington orchestra's signature song, "Take the A Train," according to PBS and many other popular pieces, Ellington also had a prolific career writing solo works.