A lead sheet is a type of notation that includes the melody (“lead” line) and chord symbols, and less critically, other information such as arrangement notes, lyrics, articulations, and cue notation for critical events in specific instruments, such as rhythmic hits. It is intended as “just enough” information so that an ensemble can develop their own interpretation of a song. Lead sheets are most common in jazz, but they are also sometimes used in other popular genres.

One of the greatest differences between classical music and other forms is that in classical styles, performers perform note for note what they read. In other styles (usually groove based), performers are free to develop their own information based only on general guidelines of the melody and harmonic structure.

The assumption is that every instrument will use the lead sheet to develop a part that is appropriate for that instrument. In a typical band setting, a melodic instrument or singer will perform the lead line, a rhythm guitar or keyboard will “comp” chords (i.e., develop a rhythmic accompaniment part using the specified chord symbols), and a drummer will play a beat. Generally, a style indication and tempo are provided above the first measure, though this doesn’t not necessarily have to be followed.

During an improvisation, the lead sheet’s chord symbols are used as a possible pitch sources for the melody, with additional consideration to the key signature and written melody notes.

The chords themselves are also open to interpretation. While the bass is generally sure to play the 1 and 5 on strong beats of the measure, other instruments might leave these notes out, favoring guide tones (3 and 7), indicated tensions (flavors of 9, 11, and 13), and possibly substituting other tensions that are not indicated for the specified chord tones. One of the traditions in jazz interpretation is to find richer chords than what were originally specified, in a practice known as "reharmonization." Thus, lead sheets are intended as starting points for performances, where an ensemble can create its own unique interpretation of the song. For this reason, different artists’ renditions of the same song can sound radically different. This spirit of individual expression lies at the core of jazz.

Collections of lead sheets are often called “fake books,” because they allow musicians to “fake” knowing a piece on a gig, even though they never have played it before. The Real Book is a large and well-known collection of lead sheets. Originally, it was published and distributed illegally by students at Berklee College of Music in the 1970s, based mostly on handouts from their teachers. Today, it is legit, now available with all copyrights cleared (one of the great administrative accomplishments in music publishing/licensing) from Hal Leonard Corporation in a multi-volume series.

 

[Author's Note: Various notation types, such as lead sheets, Nashville notation, and other chord charts, are discussed in my book Music Industry Forms [Berklee Press, 2014].)