A short section on type providers would be fantastic. I think it could match perfectly with section 6.3.

BTW: The most interesting computer book I have read in years!

Glad you're enjoying it, thanks .

You're right, it would be nice to have a section on type providers but there's already a lot to fit in the book so there isn't really room to go into it in depth. A short note might fit, at least, just so the reader knows they are available, and where to go to find out more.