If you return to Kreechdaup after getting the Great Machine and the drill working, you'll see the Kreechda are reproducing (by budding).

The leader Oochdar says he wants to teach his son their history, but the Nobles stole their book of knowledge, and asks that you get it back.

I've looked around, especially at the Noble Mutrizzba Shrine and the Distillery, and spoke to the last remaining (non-mongrel) Kreechda in the cage, but never found the book.

Has anyone completed this side-quest?

Yes, the book can be found somewhere else (no spoilers). Good luck!

Can you give a STRONG hint? Or just tell where it is?
I played through the whole game without walkthroughs but I'm stumped on this quest.