Fake book

A fake book is a collection of musical lead sheets intended to help a performer quickly learn and perform new songs. Each song in a fake book contains the melody line, basic chords and sometimes lyrics – the minimal information needed by a musician or small group to make an impromptu, extemporized arrangement of a song, or "fake it". The fake book is a central part of the culture of playing music in jazz, where strong improvisation abilities are expected from "comping" rhythm section players (piano, electric guitar, double bass, drum kit) and "lead instruments" which play the melody and improvise lengthy solos over the chord progression.

Fake books are not intended for novices. Sometimes, melodies with syncopation are written with the syncopation omitted, so the reader must be familiar with the songs "by ear" to play the melodies correctly. Some 32 bar forms do not have a printed melody during the "B" section, as the lead instrumentalist is expected to improvise one. Similarly, the chord progressions for some blues tunes omit the turnaround (often simply indicating two bars on the tonic), as it is expected that an experienced jazz player will know the appropriate turnarounds to insert (e.g., (I–VI⁷–ii–V⁷). The reader needs to have thorough familiarity with extended chords (e.g., C¹³) and altered chords (e.g., C^7♯11). Introductions and codas are often omitted, as it is expected that players will know the familiar intros and codas used on specific songs. Fake books are often bound.

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Wikipedia