No, I haven't used or even played with the interface series. We are just beginning to look at setting up a foundation for n-teir development. I have been reading Markus' book "Advanced Object Oriented Programming with Visual FoxPro 6.0". He describes some of the classes he uses and they had sounded like a possible place for us to start. The interface series was less appealing to me at this point than the other three. I'd like to get a feel for what some of his Data and Business classes do and how they interact.