Star Wars returned with a bang a few years ago with the release of Star Wars: The Force Awakens, which took place about 30 years after the conclusion of Star Wars: Return of the Jedi. Certain events from those missing decades are alluded to in The Force Awakens, but really, there's a lot we don't know about what happened to Luke, Han, Leia, and the gang. There's a lot of untapped potential there, but Lucasfilm might be getting ready explore this time period. Get your tin foil hats on because new movies set between Return of the Jedi and The Force Awakens may be on the way at some point down the road. Why do we think so? Because, apparently, nobody is allowed to write books about it.
Podcaster and writer Bryan Young was in attendance for the book launch of new Star Wars books, where authors Claudia Gray (Bloodline) and Delilah S. Dawson (Phasma) were answering questions and signing copies. When asked what other Star Wars books they'd like to write, Gray answered that she'd like to write a sequel to her Star Wars young adult novel, Lost Stars. However, she can't do that yet because the story would have to take place after the Battle of Jakku and the Star Wars story group has not yet opened up that period to writers.
The main thing to take away from here is that there is currently a lockdown on writing stories that take place post-Battle of Jakku, which was the final major battle between the New Republic and the Galactic Empire. A possible reason for that is that Lucasfilm is looking to tell those stories in movies and doesn't want anyone contradicting whatever it is they are planning. There is some precedence for this. George Lucas had a similar embargo on stories set during his prequel trilogy because he wanted to be the one to tell them.
That period of time is rife with potential stories, no matter what form they come in. Just based on what we know, there's Luke forming his Jedi Academy; Ben Solo's training under Luke; Kylo Ren destroying the Academy; The rise of the First Order; and any number of events that could have happened in those 30 years. Basically, it's prime storytelling real estate, and there's a wealth of material sitting there just waiting for someone to pluck.