Took me a while to finally come back and write a review.
Overall I have enjoyed it a lot and can recommend it to any technical person who does doing web development or wants to understand the web better.
There is good balance of history of HTTP protocol, practical tip, tools recommendations and deep dive into the HTTP/2 protocol.
Though it's hard to asses how this knowledge can be used by a regular software developer, it helps to become a better specialist having deeper understanding of how technologies/protocols work.
In the case of HTTP/2 in Action it gave a better understanding of what happens on the client side when a user goes to your website, then how it reaches the server (CDN, DNS, reverse proxies, etc.) and finally how to configure your server for the best performance and security.