I’d recommend “The Little Book of Bonsai” by Jonas Dupuich. His forum “Bonsai Tonight” is also a great resource. I’d also recommend the “Bonsai Nut” forum.
I think “The Little Book of Bonsai” by Jonas Dupuich would be a great starting read for ya!: https://www.amazon.com/Little-Book-Bonsai-Guide-Caring/dp/0399582592/ref=nodl_
I fucking love bonsai, but I'd get the instructor a bonsai book instead. If you don't know bonsai it's easy to pick up something that's overpriced and not of high quality, especially as they are often sold out of zone.
This is a good one, though I haven't read it. Jonas Dupuich is unquestionably an expert in the field and a damn nice fellow to boot.
This one's pretty nice and represents a collaboration between Peter Warren, and Ryan Neil, two of the best in the world, both apprenticed in Japan.
This is a beautiful book from Kunio Kobayashi the master at Shunka-en, it's pretty but carries little information. That's ok, great coffee table book.