Star Wars Legends: Shadows of the Empire
This novel takes place between The Empire Strikes Back and Return of the Jedi. It focuses on Luke, Leia, Lando, Darth Vader, and Xizor. Essentially, both Darth Vader and Xizor are hunting for Luke Skywalker while Luke and his friends are looking for Han Solo. Darth Vader wants to capture Luke and turn him to the dark side of the force while Xizor wants to kill Luke in retribution for a past transgression that Vader caused him. It's an interesting dynamic, but the implementation isn't very interesting.
The book also introduces a one off character, Dash Rendar. He fills in the smuggler role while Han is frozen in carbonite. He's an annoying character and I'm glad he's not recurring throughout the series.
Overall, it's a filler book. If you've seen the movies you know exactly where the characters are at the start and end of this book. It makes the whole thing feel pointless.
I should also mention that the audio book version really annoyed me because the narrator kept pronouncing names wrong in the universe. Emperor Palpatine and the planet Coruscant are pronounced incorrectly throughout the entire performance. And it's not much of a performance. It's much more like someone reading a book to you and less like a talented voice actor performing the bookk. It does have sound effects and music, which help out a bit I suppose.
As far as my recommendation. Well, It's not a very good book, but it does help flesh out the events that transpire between The Empire Strikes Back and Return of the Jedi. If you feel like there's a conspicuous gap between the movies then maybe you should give Shadows of the Empire a try. I think, for most of us, this novel is better avoided.