8. Splinter of the Mind’s Eye
No list of supplementary Star Wars content is complete without Splinter of the Mind’s Eye. Now outside of canon, it was upon publishing the first full-length novel exploring the what-ifs after A New Hope and two years before The Empire Strikes Back. This is the quintessential extension novel, and perhaps the truest representation of Expanded Universe there ever was or ever will be. In fact, it was created with the intention of extended the Star Wars universe if the film bombed.
Luke and Leia are in separate fighters and an energy storm causes both of them to crash on the swampy planet of Mimban. Along with C-3PO and R2-D2, they search for the Kaiburr Crystal. One of the unique artifacts that augment The Force, the Kaiburr Crystal can be used to generate Force lightning, heal injuries, and energize Force-users in close proximity. Naturally, Darth Vader is the primary villain, and stalks/fights Luke and Leia through the novel until the ultimate finish.
Inspiration for future films
Perhaps the most amazing aspect of Splinter of the Mind’s Eye is the stark number of details that either resemble or contradict future movies. The world they crash on is Mimban, which bears a striking resemblance to Yoda’s home planet of Dagobah. Some “hairy aboriginal creatures” on the planet could easily be the precursor to either Ewoks or Wookie. Finally, since this novel is between the first two movies, there’s a lightsaber battle in which Luke slices off Darth Vader’s mechanical arm, which is a completely bizarro world for fans.
And if that’s not enough, decisions about the novel were planned to actually impact a second movie. George Lucas actually advised against a space fight causing the crash, because he knew it would cost too much in FX budget. It obviously doesn’t fit Star Wars now, but Splinter of the Mind’s Eye is an important part of Star Wars history.