How to do a business logic layer?

Thank you.

It was all working but I have heard (or read) people saying things like 'a model should not call a model' or similar.

I thought about using libraries as well but they didn't seem appropriate as there is no stand alone or contained logic to them. i.e I could not use the library anywhere else, which is how, rightly or wrongly, I regard libraries.

Thank you for the response. I am really looking forward to working with this approach! :-)

Paul.