6 books in series

The Making of Star Wars

The Making of Star Wars is a 6-book series with 6 released primary works first released in 1999 with contributions by Laurent Bouzereau, Judy Duncan, Jody Duncan, and J.W. Rinzler.

The Making of Star Wars: Episode I - The Phantom Menace
Mythmaking: Behind the Scenes of Star Wars: Episode 2: Attack of the Clones
The Making of Star Wars: Revenge of the Sith
The Making of Star Wars
The Making of The Empire Strikes Back
The Making of Return of the Jedi