Every now and then even the best practitioners must take a step back to re-ground themselves in the fundamentals of the trade. The "blocking and tackling." Chris Date does a great job lecturing about logic and set theory—the blocking and tackling of the relational model. No one is more qualified to show us where the tools of our trade have munged the model. And his presentation style makes it a pleasure to learn.
Data Architect, Lifetouch Inc.