I Believe in You is a 1961 Broadway show tune written by Frank Loesser for the musical How to Succeed in Business Without Really Trying, introduced by Robert Morse as J. Pierrepont Finch. The protagonist sings it to himself in the mirror while shaving, and in the movie version Rosemary also sings it to Finch. The song is a classic show tune from a Broadway musical and has been covered by many artists, including Anita O'Day on Time for 2 (1962), Peggy Lee on Sugar n Spice (1962), Jack Jones on She Loves Me (1963), Sarah Vaughan on The Explosive Side of Sarah Vaughan (1963), Nancy Wilson on Broadway – My Way (1964), Frank Sinatra with Count Basie on It Might As Well Be Swing (1964), and Shirley Bassey on Shirley Stops the Shows (1965). Genre: Broadway show tune.
