Christie Golden 
Star Wars: Fate of the Jedi – Omen [EPUB ebook] 

Luke and Ben Skywalker continue on their quest to learn the ways of non-Jedi Force-users and to try to understand just what went wrong with Jacen Solo that caused him to become a Sith. In the meantime, Han, Leia, and Jaina Solo — along with Jag Fel and the other Jedi — try to deal with the escalating problem of Jedi Knights seemingly going insane…