Excellent for those that are completely new to the game.
There are several beginner books out there, this one fits well those people that pretty much have never played a game and need to learn about the objective and rules of the game. People that are beginners but have already played a few games, understand about captures and basic life and death will probably be better served by going straight to Volume 2 of this series or look for a different beginner book, such as Go for Beginners by Iwamoto.
The book consists of two parts, with the first one focusing on Fundamentals and the second one on Basic Techniques. In the Fundamentals, the authors do a very nice job in explaining the basics of the game. This is why I am recommending this for people that don't even know about the rules, since here they will get a step by step explanation on the objective of the game, how play works, capturing, illegal moves, the rule about ko and counting territory at the end of a game. They use diagrams generously and even beginners won't need to grab a board in order to follow the explanations. They also do a very good job with terminology, which can be overwhelming. Thus, they use the English name for many of the terms and only in important cases revert back to the Korean or Japanese names, with a clear explanation of what they mean of course.
Compared to the book by Iwamoto mentioned above, the examples here are much simpler. When explaining connecting and cutting the authors focus on the basics and stop there. At least in the Fundamentals part, when they move over to Basic Techniques there is a little deeper examination of capturing (ladders, snapbacks, throw-ins, etc.), connecting, life and death, capturing races, ko fights, and endgame. In the book by Iwamoto, the examples are much deeper and require the reader to have some experience with reading (being able to mentally calculate a sequence of moves) in order to understand some of these.
I particularly liked the test questions at the end of each chapter, since these allow the reader to check and see if she understood properly the concepts that were presented. There are special sections throughout the book with additional information, such as where to play on the internet, how go rankings are defined, and many others.
Those people that are brand new to the game can seriously benefit from reading this book, but those that have already some experienced will likely find it too basic and will be better served to look at the options mentioned above.