Star Wars: Split Horizons follows the author's original novel - Star Wars: Awakening - and further develops the alternate plot lines and new characters he introduced in the original.
Is there a third book to follow to make it a trilogy? I hope so because Split Horizons is a worthy successor to Awakening. Its hard to put down.
Too bad Lucas didn't have access to the plot ideas. And the characters which are introduced. Maybe he could have avoided Jar Jar!
Lucas doesn't plan on making any more Star Wars books. Maybe an animation team somewhere will pick up these books and turn them into a series.