I am writing a book per CRC press with Lee's blessing, but it won't be distributed via TGC channels at all due to the contract I have with them. It will be about 450 pages, lots of pics/illustrations/etc. A complete start to finish tome on how to use, build, and configure Game-Guru. I've been conducting interviews with lots of our 'leaders' in the Game-Guru market on various topics ranging from level design, prep, marketing, sale, etc. So you could always wait for that but it's not due to hit print until about July of next year.
I have no idea what the price will be but the publisher will set that. I will however have access to discount coupons I can give out to forum members, which should help ease things.
In the interim, I'm sure the community will come up with something. I unfortunately cannot participate as it may (unsure) violate my contract to do so by working on a competing product. I've tried to turn my blog into a general repository of Game-Guru things so definitely check it and specifically the tutorials and reference sections.