I'm no expert in C++/CLI or .NET, but I also own C++/CLI in Action and can really recommend it.
It does only give a small introduction to the .NET framework and doesn't really introduce any parts of the huge .NET library. But it gives you a solid introduction to its core principles.
The good thing (for you) is, it is targeted to someone who already knows C++ and OO in general and in the first part it explains the new language features introduced by .NET (which can also be found in other .NET languages, therefore being useful beyond C++/CLI) and the differences to classical C++.
One of the major topics of the book is the interoperation of managed (.NET) and unmanaged (native) code, as this is one of the main strengths of C++/CLI, therefore in the second part it describes the many possiblities and pitfalls of mixing native with managed code.
The third part elaborates a bit on using major .NET frameworks (like Windows Forms or WPF) with C++/CLI and concentrates on using these from native C++ applications.
Although this book won't give you an introduction to the huge .NET library (for this you might want another book, which will surely use C# or something more naturally .NET), it explains all of the .NET language features (that are the same all over the major .NET languages) and is especially useful if you want to use C++/CLI to combine classical C++ code with .NET code, as it explains all the pitfalls and possibilies (that range much wider than PInvoke, known from other .NET languages). For example, I myself used it when I needed to use a library that only had a .NET interface in my native C++ application.