@KRAW@KRAW@linux.community, It's a deep dive, pretty rewarding. The basic food science, history, and a lot of things to try. Really nice alongside the NOMA Guide, actually.
I've grown many batches of koji (it gets easier as you learn more about how it behaves), but my one foray into store-bought stuff wasn't too bad — it seemed a bit dry, but that's easily enough remedied.
We have an early edition of this on the shelf in our kitchen; yes, it's terrific.