Welcome to the “other side” Paz!
Good decision to start with books. Unfortunately there isn’t something like a “basic work” on armor. At least nothing in English (but of course in Japanese!).
A few books dealing with individual parts, like helmets, masks or the cuirass, but nothing comprehensive.
Except “Chūkokatchū Seisakuben” by Sakakibara Kōzan, translated by R.Robinson. Also Markus Sesko wrote “Katchū”, but I think it’s only in German…
Other works are:
“Watanabe Art Museum/ Samurai Armor Collection” by Trevor Absolon & Dave Thatcher
“Tokugawa Clan & Bakufu Daimyō Samurai Armour Sets” V1 by Trevor Absolon
“Samurai Armour” V1 by Trevor Absolon
”Helmets of the Saotome School” by Teruo Orikasa, Luc Taelman, Jo Anseeuw
”Stirrups of the Samurai” by Teruo Orikasa, Luc Taelman, Jo Anseeuw
“Japanese Arms and Armour” by Ian Bottomley
”Japanese Armour” by L.J.Anderson
”Japanese Arms & Armor” by R.Robinson….
….for example.
Well, there are a lot of “coffee table books” as also auction and exhibition catalogs!
If you seriously interested, you can try here: https://www.japanesearmorsociety.com/