Star Wars: Dark Force Rising is book two in a three-book cycle. It is part of what has been referred to as “The Thrawn Trilogy”. All three books were written by Timothy Zahn. It is my understanding that this trilogy is not considered to be canon in Star Wars lore. Personally, I enjoyed the first book in the series, Star Wars: Heir to the Empire, and was equally impressed by this second book.
I would recommend that people read Star Wars: Heir to the Empire, the first book in this trilogy, before diving into the second book. Book Two picks up shortly after Book One left off. Skip the first book, and you miss out on much of the plot that continues to weave through the story. In short, this book has an impressive amount of characterization and backstory on a race that could easily have been neglected. It also is filled with political intrigue.