This book is basically an extremely abridged re-hash of all 6 movies;in fact, some lines in the book are directly from the movie. It does shed light on a few unanswered questions, but all in all, it is definitley geared toward younger readers. If you've seen the movies and read the expanded universe novels, you're better off not wasting your time.
Now, if an "adult" novelist (i.e. Timothy Zahn) were to pick this one up and write an "adult" version, it would be worth the read.