I really liked this one; the little opening vignette does a nice job of setting up the theme of the book. As subsystems go, this one is pretty simple, and it will incorporate nicely into an existing game with a minimum of fuss. Unlike the other reviewer, I have no particular problem with the alignment system as it exists, though I do use a numerical sub-system from the Book of Hallowed Might for descriptive purposes. Anyway, the system described herein isn't any more unbalanced than the paladin class - purifying flames are great at destroying evil things (unless those evil things are resistant to fire) but leave good (and usually neutral) things untouched by the flames. Very cool. I will be using this book's material HEAVILY in my campaign for followers of my Sun/Justice god.
[5 of 5 Stars!]