Like most of us here, I am full of admiration and grateful for the work of K2's authors (not to mention Joomla! itself).

However I have been unable to find a source of detailed and systematic documentation of the kind one can find for Linux explaining every option fully and accurately; the interaction between K2 and Joomla!; K2's overall structure ...

There are some excellent videos of course, but they only demonstrate what they choose and ignore other possibilities, no doubt for good practical reasons but these gaps can be a source of real difficulty for learners trying to go beyond the basics.

Has anyone published a serious book or wiki on Joomla! with K2?

I hope I am wrong about this ... I'd be very pleased to be corrected.

In the meantime I'll struggle on to find out why one needs "Item view options in category listings" as well as "category view options" and "item view options": experimentation is a slow way to learn :)