Tamar,
One of the things that confuses me most is the affect of various SET settings on how VFP will process a SQL query. This might be a great chapter in and of itself?
As for SQL examples, I've always been interested in "self referential" (not sure if that's the right term) queries where a single table has a logical tree like structure, i.e. where one person reports to another who reports to another etc.
I'm looking forward to your ebook!
Malcolm