DNN - great but limited text books

I guess one of the things that is a frustration is the lack of good text books on Dot Net Nuke - our CMS of choice (DNN).

Maybe it's an age thing but it is useful to have a couple of text books to refer to from time to time. It does mean of course that our DNN development skills can be in high demand - it's a big system and needs good people to make the best of it. But it would be nice to have a few more easy to read manuals around - still there is always Google I suppose.

And in the end that is where developers head to first - the information is probably fuller and more uptodate than any text book could be.