A long awaited update (admittedly, I skipped the 5th edition). More focus on "soft" values, which was sorely missing in the 4th edition as well as some refinements on the process steps.
This is something as unusual as a compilation of knowledge that is actually readable. Of course, you get the most out of it if you're already a PM, as it may be hard to digest everything without previous experience.
If you're into Project Management, you should definetely have this in your bookshelf.