I some time ago wanted to read about how the Vatican state functions. It was, however, quite difficult to find a serious book on the topic. Most books were nonsense about the secrets of the Vatican or what the Vatican doesn't want you to know. Other books were just too old (I found a French book from the 1960s, which would be really dated by now). This book, on the other hand, was spot on.
This is the book for you if you're interested in knowing how the Vatican works, including the economy, employees, educational organizations and infastructure. It gives a good depiction of how the Vatican state is working and the structural problems of the state and the Catholic church, without bringing in the normal nonsense found in these kind of books.
The book was written back in the 1990s but has aged surprising well. The book does, for example, give some idea to why the late pope Francis reformed the curia (predicate evangelium) and a detailed description of the history and current functions of the Cardinals. It also answered questions I've been wondering about for quite some time, like whether conferences of bishops (mandatory per kanon 444) is a recent development, which this book confirms; the book is a fountain of facts difficult to find elsewhere.