Legacy of the Force: Inferno

Inferno is the sixth book in the Legacy of the Force series. It is a paperback by Troy Denning and is due out in September 2007. According to Denning in an interview, the book "will feature many of the same characters who survived Tempest—and that Jacen will finally discover who his true enemies really are."

Amazon.com synopsis
The galaxy is in turmoil due to spreading and incresingly violent civil war - and the Solo/Walker clan is in shock after the horrifying murder of one of it's most beloved members. Jacen Solo, now a full Sith Lord, has seized control of the Galactic Alliance. Luke Skywalker's judgement is clouded by grief, even as he faces his most momentous decision since becoming Grand Master of the Jedi order: whether to support Jacen's illegitimate government against the forces threatening Coruscant...or to join the Rebel Confederacy and take arms against the Galactic Alliance he helped forge.