Saw this at the library when I was in need of a read. I've been in tech for a long time and even dealt with zero trust networks a bit a decade ago, so I was curious. It's an excellent book for the technically adjacent reader.
There's almost no code, and that's simple. What the book has is detailed descriptions of risks, the designs needed to address the risks, and excellent case studies in each chapters to show real world points about the subject
Simply put, the edge of your business network, usually firewalls, is not sufficient to provide true security in the modern age. You need to take actions to protect communications and data throughout the organization. If you're an IT management, product manager, or in a related position, this is a great starting point.