I'm not a DBA, just a lowly web applications developer who happens to use MySQL as a backend most of the time. I've been developing with a lot of nagging questions in my brain: "How do you set up a master-slave replication?" "How do you roll back the database to a past point in time?" (The kinds of nagging questions that, as a Django or Rails developer, tend to be "someone else's problem.")
This is a brilliant and powerful book. I picked this up in the bookstore and couldn't stop reading it. It's not the only resource available on MySQL replication, monitoring, and clustering, and another title, High Performance MySQL: Optimization, Backups, Replication, and More, has a few chapters that overlap with the topics in this book.
That being said, I liked the tone and pace of this book, and it goes more in-depth than many other similar titles that cover the same material. It made concepts stick to my brain like no other MySQL book I've read so far. The authors make the material very accessible, even though it's not easy subject matter. For me, it shed a lot of light on some mysterious MySQL topics.
It's not a beginner's book, but if you've been working comfortably with a MySQL shell at a startup for a while, are interested in digging deeper, and you're looking for an excuse to buy another computer book, this one is definitely worth it.