A Real Book chart is often based on the most popular version of the tune, not necessarily the original. For example, Autumn Leaves and Black Orpheus are from the Sinatra versions.

And, as stated in other answers, these charts are often simplifications.

A Real Book chart is often based on the most popular version of the tune, not necessarily the original. For example, Autumn Leaves and Black Orpheus are from the Sinatra versions.

And, as stated in other answers, these charts are intended to show the conceptual framework of a tune, rather than capture nuance of a particular version.