The book is quite lengthy. If you want to read it from start to end, you will have to go through 444 pages. The intended audience is described as "manager, developer, coach, ScrumMaster, product owner, analyst, team lead, or project lead". While this is not completely wrong, I perceived the different chapters as very different in regard to the target audience. No matter what role you would grab for yourself, not all parts of the book will be equally relevant for you. The first part of the book is called "Getting Started" and consists of the sections Why Becoming Agile Is Hard (But Worth It), ADAPTing to Scrum, Patterns for Adopting Scrum, Iterating Toward Agility, and Your First Projects. Cohn goes into the field of organizational change here and tries to explain, how such an endeavor should be undertaken. However, I felt in reading it, that he focuses very much on the developers and clads a developer's position whenever possible. This is not bad, but might be hard to follow for a manager. In addition, Cohn creates his own model for organizational change while going with established ones (e.g. John Kotter) might have been sufficient and less confusing. This first part of the book will be especially helpful for Scrum Masters new to organizational change and people striving to become coaches. In addition, managers with a development background will benefit from it.
The second part of the book focuses on Individuals. It includes the chapters Overcoming Resistance, New Roles, Changed Roles, and Technical Practices. I liked this part of the book very much, because the roles (both Scrum and traditional ones) are described in depth. Cohn also shows attributes of "good" Scrum Masters and Product Owners, which is helpful if you want to find appropriate people to fill those roles and haven't extensive experience, yet. Of special interest for the reader are the hints about tech leads or programmers as Scrum Masters. They are worth a read for managers as well. This reading group will also benefit from the section about the changed leadership role. The last chapter focuses on technical practices (as the name implies), which marks a shift of the audience focus away from manager / Scrum Masters into the direction of developers.
Consequently, the third part of the book "Teams" deals with Team Structure, Teamwork, Leading a Self-Organizing Team, The Product Backlog, Sprints, Planning, and Quality. Those chapters are a treasure for Scrum Masters and developers. Here, the author describes in detail how Scrum works and provides some best practices as well. Basically, this part helps somebody setting up a new Scrum team to make less mistakes. Some paragraphs are interesting for Product Owners as well, but those might decide to let the Scrum Master educate them about it.
In the last Part ("The Organization"), Cohn goes into Scaling Scrum, Distributed Teams, Coexisting With Other Approaches, and Human Resources, Facilities and the PMO. Personally, I didn't like this part. In my opinion, Cohn doesn't dive deep enough into those topics. However, they will be of great value for people starting with Scrum and Scrum Masters who haven't done that several times already. In any case, it is worth to take a look at those chapters.
Finally, Cohn gives a brief look into the "Next Steps" where he tries to cover metrics and agility assessments. Well, don't expect too much from that - I wasn't impressed at all. It is not more than a brief glance at the wide field of metrics. Again, this will be helpful for Scrum Masters trying to get an overview or starting with that topic.
In summary, again, I liked the book a lot and recommend you to read it. However, it is entry literature - not an advanced guide to organizational change. If that is okay with you, go for it!
Are there any books you DO recommend as an "advanced guide to organizational change"?
well, there are tons of literature out there. Most of it is rather superficial though. So far, there is only one book that explicitly talks about organizational change and Scrum - but it's only available in German and the author is myself.
If you are in for a deep dive on organizational change, you probably want to start with John Kotter's "Leading Change", continue with Schein's "Organizational Culture and Leadership", Deal's and Kennedy's "Corporate Cultures", and Cameron/Quinn's "Diagnosing and Changing Organizational Culture". Once you have gone that far and still want to dig deeper, top it with Martin's "Organizational Culture". This should put the other books into perspective.
You will have many ideas and notions then. Most likely, you will also have identified an area where you want to investigate further. However, with organizational change it's similar as with being a good Scrum Master: You can read as much as you want, visit courses by the dozens and still won't improve much unless you put your knowledge to daily practice.
Best
Dominik