Jedi Apprentice: The Call to Vengeance

The Call to Vengeance is the sixteenth in a series of young reader novels that chronicle the adventures of Qui-Gon Jinn and Obi-Wan Kenobi prior to Star Wars Episode I: The Phantom Menace.

Publisher's Summary
Revenge is very much a human trait, but it is forbidden for the Jedi. Qui-Gon Jinn, driven to the edge by a shattered heart and beliefs torn, dangerously approaches the dark side. Others, like Mace Windu and Obi-Wan Kenobi try to reason with the venerable Jedi Master before it is too late.