The nutshell series of books are supplements that are usually intended for people currently in law school taking a class pertaining to the subject. In my case, I never took intellectual property in law school, instead, I went back to school to get an engineering degree so that I could practice patent law. This was one of the sources I used to get familiar with patent law before I started studying for the patent bar exam. This version of the book was put out before the America Invents Act which changed some of the rules about who can get an invention, so some of the information, especially at the beginning of the book is dated. However, much of what is in the book is still very applicable and while it is not an in-depth treatment enough that you could sit down and write your own patent or pass the patent bar exam, it will give you a high-level overview of patent law, and can still be used as a reference.
It walks through the history of the United States patent system and the concepts of patentability, claims, claim construction, infringement, and a brief introduction to the various international conventions. While it would be more helpful to patent litigators, there is still good information for patent prosecutors and that those people who want to attempt to take on the challenge of writing their own patent can use. And, it can easily be used in conjunction with Patent it Yourself and its companion books (although there is a lot more legalese in this, as you would expect). As someone who is becoming a patent attorney in reverse (I got a law degree, then went back to undergrad to get an engineering degree) I started reading this as I was finishing school to get the basics of patent law that I did not learn in law school, then read Patent it Yourself to get a better idea of the nuts and bolts of the patent application process, and will eventually get a copy of the Manual of Patent Examining Procedure, which is what you are allowed to use when taking the patent bar.