The Real Book is a compilation of lead sheets for jazz standards. It was created in the mid-1970s by two students at the Berklee College of Music. In its original form, it was an illegal publication made at local copy shops. It quickly became a standard reference for musicians. Two additional volumes were bootlegged in subsequent decades.

In 2004, Hal Leonard released legal versions of the three Real Book volumes.

Jazz is largely an aural form where musicians learn music and improvise by ear. Much of the music was not expressly written down. When a song was notated, it often employed the sort of shorthand notation familiar to continuo players in the Baroque era: a melody would be accompanied by numbers and symbols to indicate the harmony. Jazz notation would typically include a song's melody and an outline of its chords. This shorthand notation became known as a "lead sheet". By the 1940s, lead sheets were being collected into books and marketed to musicians in trade journals. Because a musician could credibly bluff their way through a song they did not know by playing off a lead sheet, these collections were called "fake books".

One precursor to The Real Book was George Goodwin's Tune-Dex service, which was designed to help radio programmers keep up with the newest songs. Each Tune-Dex card included publishing information on one side and a lead sheet on the other. Goodwin began marketing Tune-Dex to musicians as well, even though he was breaking his licensing agreements with music publishers by doing so. Eventually, Tune-Dex cards were bundled into fake books and sold widely.

In order to legally print music, the copyright holder must give permission. In the 1960s, the United States Code Section 104 of Title 17 allowed for a punishment of a year in prison or a fine of $100–1,000 for each instance of copyright infringement for profit. Fake books with hundreds of songs created massive criminal liabilities for their publishers. The FBI took notice and prosecuted some of the more egregious distributors of such books. The first prosecution under the law took place in 1962. This coincided with the rapid decline of sheet music sales. Recordings had long displaced sheet music as the most lucrative profit center in the music industry. By the late 1950s, sales were so low that hit songs were not guaranteed a sheet music publication because it might not be profitable.

A music publishing sea change was underway in the 1960s as musicians gained a general understanding of how it worked. Composers frequently lose out on income by signing away or being tricked out of maximizing their publishing rights. Duke Ellington was exploited by people like Irving Mills, who would make dubious writing claims to siphon off part of the publishing income from a song like "Mood Indigo". Ellington established the publishing company Tempo Music in 1941 to control his intellectual property. In the 1960s, more musicians began to create publishing companies as they possessed a more sophisticated understanding of the business. Jazz musicians also realized the benefit of writing their own tunes, however inane, in order to earn publishing fees from their performances and recordings. Jazz standards written by other composers began to lose market share to original compositions.

The Real Book was created by two Berklee College of Music students. Because of the illegality of their project, the compilers of The Real Book have remained anonymous, even though their identities are an open secret. One was Pat Metheny's student and the other was in Gary Burton's studio.

Burton's office had a filing cabinet full of precious lead sheets that would often be raided by curious students. The charts were for Burton's band, and they included tunes by Metheny, Steve Swallow, Chick Corea, Mike Gibbs, and Keith Jarrett. The two students created a music folio that combined their teachers' songs along with jazz standards. Metheny recalls the students as "funny guys" who loved the joke of dubbing their fake book The Real Book.