This series has been highly praised, not because it's the best it can be, but because it's the only one of its kind. For me, it seemed like a well-researched guide to a medieval city, with the word "magical" tacked on. There are craft guilds, thieve's guilds... and a wizard's guild. There are pubs, armorers...and alchemist's shops. Otherwise the society is unchanged.
This is fine for a class-based d20 game where wizardry is confined to a few character types. But what if you have a more open skills-based system? What's the effect of having lots of people knowing a little magic? Really thinking it through, how would magic change a society?
In all though a good introduction to the subject. Can't imagine why they aren't charging for it.