Definitive Books

I'm a filmmaker and educator with an attachment to Godzilla. I own a lot of books that cover the development of my favorite films, but I'm really only interested in thorough books. Basic art books and commonly known history are not interesting to me. The Insight Editions line of "Ultimate Visual History" books are pretty good, particularly the ones covering Jim Henson's material. Those have pitch documents, concept art, set photos, script excerpts, interviews, and a lot of information I hadn't actually encountered before. I'm having a hard time finding anything comparable to that for Godzilla- the first film, the series, or any of the Japanese films. The "Art of Shin Gojira" book looks promising, but as far as I know is only in Japanese. Visual or not, I'm looking something exhaustive. Recommendations?

TL;DR- What do you consider to be the definitive written works on Godzilla films?