The Layout and Strategy of Aperture
I read that training book. It's very good. However, each person learns differently. I prefer a hands-on approach (which the book was all about) but for what I usually do. So if I have a question about what I want to do, I search the guide or the book or Aperture help for that particular problem. I don't see any point in memorizing the shortcuts of sorting the shots of a wedding session if I am not a wedding phtographer (or sports event or alike). I will forget the shortcuts for lack of practicing.
But you got the idea pretty well. I suggest go to Mac Talk forum for discussing Apperture issues. You'll find much more related material.