It's a fantasic book; and you should read it.
This is one of the books that will help developers understand the best practices that lead to quality code.
I started reading this book a year after I started applying the XP practices and really striving to do what is being talked about here. Beyond Legacy Code has provided new insights and arguments for, largely, the Extreme Programming practices. There's more than just those; but it's advocating for those as a core and critical component to writing beyond legacy code. It's a simple short hand. Even if you don't do XP; this book is going to help you understand the why of a lot of other practices. It will help you understand why to bring in a lot of attitudes and behaviors around software development that will improve what you create.
I bought the book after snagging a copy off a co-workers desk and reading a few paragraphs. There's a section in Chapter 4 - Shu-Ha-Ri - that I opened it up to. Many of the books and thought leaders in the industry I find great value from apply similar concepts.
I believe Object Thinking calls these levels, informal-formal-aformal. Fred George and others use apprentice-journyman-master.
The consistency here in the leveling and what they imply of the developer is a similiarity that showed me this book was going to be worth reading; even if I got nothing significantly new out of it.
I don't think I got a lot NEW; but I got a lot of different perspective and some tidbits. I also got that I'm following a path of software development that is going to lead to being capable of producing highly maintainable code.
This is my new "Read This" recomendation when someone wants to read a book about the practices of writing better software. If they want a book on HOW; still Elegant Objects.
I used to recommend Pragmatic Programmer as that first book; but it's become dated and hasn't aged well in comparrison to other books Extreme Programming Explained or new books, like this one - "Beyond Legacy Code."