Vortex by Troy Denning

In this book, the conflict between the Galactic Alliance (and specifically Natasi Daala) and the Jedi really heats up. Meanwhile, despite their better judgment Luke and Ben find themselves increasingly forced to trust Sith apprentice Vestara Khai. This book really picked up in its second half. It's strange to be caught up with the story--now I have to wait for the final three installments (next is due in May). I just requested that the library purchase it.