Elaine Cunningham 
Star Wars: The New Jedi Order – Dark Journey [EPUB ebook] 

Following intense personal loss, Jaina Solo descends to the dark side, determined to take her revenge on the Yuuzhan Vong. In the process, she learns something new about how to fight the alien invaders, but she must also remember that revenge is not the way of the Jedi – even which it seems the only way to fight the enemy.