An excellent addition to Star Wars canon that, like so much other material, retroactively improves the prequels through the elaboration of our favourite characters' relationships.
A new Jedi character is also welcome, especially one with an intriguing backstory.
One thing that bothered me a little while reading was the way in which some of Qui-Gon and Obi-Wan's dialogue was written, it seemed a little too casual and at times whiny for two lifelong monks. I didn't have any problem with Gray's dialogue in her previous Star Wars works, maybe she just needs a little more practice writing the quite reserved Jedi characters.