Well, at the start of this book, I thought: What's new? C/S, SOA, Distributed Systems, RPCs, SOAP, etc. But after about half the book, the author manages to give a very good overview of choices and pitfalls in building distributed systems (which nearly everything is today).

Apart from some faulty references, and some errors in the examples, it would say this is a decent introduction to the concepts of Distributed System/SOA/Microservices (or whatever acronym you want to put into it today).