Original author here. Yes this book was written a long time ago when I was into the node ecosystem.

A lot of the book was copied into the official docs later https://github.com/libuv/libuv/pull/1246.

The book definitely does not capture new things. I do not intend to update it, but I still look at pull requests.

I merged it into the official docs, thanks a lot for all your work nsm! <3