[bwb]

It is frustrating, as this info should be free and accurate. Publishers only benefit if devs can play with it and build cool stuff. Google Books does have an API, but crazy rules, it can be used for private projects.

Ya, I am focused on the global English market, so USA, UK, Australia, Ireland, India, and English-speaking readers globally (a lot in Europe).

I would love to do other languages, but I just don't have the resources yet to handle that level of complexity. My hope is one day I can. I'd probably start with Spanish, French, or German.

Agreed, ISBN should be free! They are $$$.