How Harry Cast His Spell explains why the books meet our longing to experience the truths of life, love, and death; help us better understand life and our role in the universe; and encourage us to discover and develop our own gifts and abilities.
I recently listened to a podcast specializing in deep meaning in novels do several episodes on Harry Potter and the Philosopher's (Sorcerer's) Stone. It was really interesting and led to me to look for information about the following six novels of the series.
This book fills the bill. Not only does John Granger have chapters about Christian and literary symbolism, names, and themes, but he then goes through each book looking beneath the surface. This led me to reread the series for the first time in years, which I enjoyed immensely. Granger's commentary showed me some new ideas about the books and that made them even more meaningful. I enjoyed this a lot.
Definitely recommended.