Best Seller?

My respect for "Best Sellers" is gone.  Apparently the secret is to have a category so narrowly defined, your book winds up being #1.  Check out this screen shot from amazon.com:

Backstory: I did some editing/reviewing for Barron's in the past and when the author of their current AP Physics B book declined to reorganize and realign it with the new AP Physics 1 and 2 exams, they asked me if I would take on that piece and become a co-author. An interesting experience and a lot more work that I ever anticipated, but now I, too, am a "best seller"...