My friend and colleague Al Dowd pointed me to Troy Hunt's blog post last April on password entropy.
A nice thing about this posting is that it talks a lot about Rainbow Tables and how they relate to password attacks. There aren't many good, general discussions out there of Rainbow Tables. While working on the textbook, I skipped the topic for two reasons: 1) it's a specific case of some general techniques I talked about already, and this is supposed to be an introductory textbook, and 2) none of the curriculum standards I followed demanded me to cover it.
I've been fantasizing about constructing some animated diagrams to illustrate various basic concepts, but I haven't gotten to it quite yet.