I have an uncle who’s developing an interest in the subject and he has one book already but is looking for a more generic primer, something that covers all the core concepts.
Does he work somewhere with educational reimbursement? That’s a useful certification, and taking the classes would only cost about $1k-2k if you’re getting reimbursed.
I recommend Scarlet vs. Snake Eyes . . . The Battle of Hentai Mountain.
Gee Eye Jooooooooooooooooooe!