I'm about a third into this. I never imagined I could be gripped by a book where most of what is going on is aqueduct engineering. It is a facinating read, though, so far. I never realized just how advanced the Romans were.
My parents got me these for Christmas, and I ripped right through them. The final volume was apparently due in 2006, but there's nothing I can find online about it. Does anybody out there know when he will be publishing it?