Jacen Solo is one of the most well-developed characters in the Legends timeline. His experiences in the hands of Vergere and the Yuuzahn Vong changed him irrevocably. He saved the galaxy once, but to what lengths is he willing to go in order to save it again? Betrayal takes his story in a new direction, reintroducing a villain from the original Marvel comics, Lumiya, who guides Jacen along a dark path. All the while, Jacen is serving as the Jedi teacher to his nephew, Ben Skywalker, and the Skywalker and Solo clans might be torn apart along family lines.

It would be helpful to have read the New Jedi Order before starting Legacy of the Force, but we realize that's a tall order. At the very least, you'll want to familiarize yourself with the main characters and with Jacen's torture at the hands of Vergere in Traitor before diving in.