Kudos to the authors of this particular volume for having pulled together a lucid, reasonably detailed summary of the most important parts of Solaris. Despite the name, no one book can actually be a complete reference for something as complex as Solaris, but this book is a pretty good addition to any Solaris admin's bookshelf.
One of the difficulties of writing a book by committee is maintaining the same audience and consistent focus across chapters and topics. In this case, there are some chapters where the level of detail does not match what is present in other chapters. And in some cases, there is a distinct audience mis-match.
I came across one howler in Chapter 10: "differences between shells are subtle, indistinguishable to most regular Solaris 11 users." The author of that chapter goes on to explain that for that reason, the chapter will focus on bash. Fair enough on the selection of the most common shell for detailed discussion. But you have to wonder how useful a chapter is going to be if the assumed audience is too clueless to see the difference in how sh and csh (for example) execute even simple actions like setting an environment variable.
It would be nearly impossible for a book of this type to earn 5 stars. But this volume gets a solid 4 in my book.