"I Could Write a Book" is a song with music by Richard Rodgers, who composed it, and lyrics by Lorenz Hart. It was published in 1940 and comes from the Rodgers and Hart musical Pal Joey, in which Gene Kelly and Leila Ernst introduced it. The song is regarded as a standard and as a jazz standard. A Time review of the Pal Joey production in January 1941 described it as "sweet".
Notable later versions include recordings by Anita O'Day, Frank D'Rone, Vince Guaraldi, Frank Sinatra and Harry Connick Jr., whose version was used in the 1989 film When Harry Met Sally... Dinah Washington also recorded the song for her 1955 album For Those in Love. The recordings span both vocal and jazz performances.
