"Knock on Wood" is a song written by M.K. Jerome and

Jack Scholl Jack may refer to: Places * Jack, Alabama, US, an unincorporated community * Jack, Missouri, US, an unincorporated community * Jack County, Texas, a county in Texas, USA People and fictional characters * Jack (given name), a male given name, ...

for the film ''

Casablanca Casablanca, also known in Arabic as Dar al-Bayda ( ar, الدَّار الْبَيْضَاء, al-Dār al-Bayḍāʾ, ; ber, ⴹⴹⴰⵕⵍⴱⵉⴹⴰ, ḍḍaṛlbiḍa, : "White House") is the largest city in Morocco and the country's econom ...

'', where it was performed onscreen by

Dooley Wilson Arthur "Dooley" Wilson (April 3, 1886 – May 30, 1953) was an American actor, singer and musician who is best remembered for his portrayal of Sam in the 1942 film ''Casablanca (film), Casablanca''. In that romantic drama, he performs its theme ...

to music played by pianist Elliot Carpenter. Commissioned by producer

Hal B. Wallis Harold Brent Wallis (born Aaron Blum Wolowicz; October 19, 1898 – October 5, 1986) was an American film producer. He is best known for producing ''Casablanca'' (1942), ''The Adventures of Robin Hood'' (1938), and ''True Grit'' (1969), along wit ...

, the song is the movie's only original composition.

Performance in ''Casablanca''

In the film, band leader Sam, played by Wilson, sings the refrain "Who's got trouble? / Knock on wood" at Rick's Cafe Americain during an early conversation between main character and bar owner Rick Blaine (

Humphrey Bogart Humphrey DeForest Bogart (; December 25, 1899 – January 14, 1957), nicknamed Bogie, was an American film and stage actor. His performances in Classical Hollywood cinema films made him an American cultural icon. In 1999, the American Film In ...

) and black market dealer Guillermo Ugarte (

Peter Lorre Peter Lorre (; born László Löwenstein, ; June 26, 1904 – March 23, 1964) was a Hungarian and American actor, first in Europe and later in the United States. He began his stage career in Vienna, in the Austro-Hungarian Empire, before movin ...

). The conversation introduces stolen letters of transit, a plot device that drives the ''Casablanca'' story and personal turmoil for Rick. The song foreshadows the role the letters of transit and Ugarte will play in the story and for Rick.

References

Casablanca (film) {{1940s-song-stub