I can't speak to the rest of the book, which seems like a pretty ambitious effort, but the crypto content needs to be burned out of it with a scorching torch.
What resources on security would you recommend for developers that are not specializing in security?
There are a lot of land mines of misinformation on the Internet today.
"Security" is a big topic. For cryptography, a good (but inadequate) starting point is _Cryptography Engineering_. If you write cryptography the way this book suggests you should, you will implement egregious vulnerabilities.