Max C externals tutorials?

I would like to get started in building my own C externals for Max, but any tutorials, books, pdfs, etc.. I can find are older (8 - 10 years old or more)... so that brings me to these questions:

Is this older information still relevant? Is everything involved basically the same or close enough where I can follow that older information?

Is Eric Lyon's 2012 book still up to date? If not, are there updates documented anywhere? I see it was written for Max 5, and there is an additional chapter describing Max 6... is there anything similar for Max 7 (maybe Max 8)

Do you have any recommendations for reading, videos, classes, tutorials?

My past experience with older tutorials and books involves spending many hours over many days to finally discover that there has been a very slight change to the boilerplate setup code, or something small like that. Which is why I'd like to make sure the information I'm finding is still accurate.