No, they are not books for beginners, or those needing help transitioning from a PC to a Mac*. But they are excellent reference books to have on your desk. Good indexing means you can find relevant information in just a few seconds. But if you have some computer knowledge and basic familiarity with a Mac they should be invaluable. And if you are a bit of a nerd, they can be enjoyable reading as well.
The author, David Pouge, used to write the IT columns for the NY Times and has a way af making complex stuff understandable.
I still find my 'Lion' version (OS X v10.7) useful even though I'm now using Yosemite (v10.10).
*Help for this really isn't needed. Apple's web-site covers all the critical bits. Anyone familiar with a PC will not find it difficult.
Good luck, not that you will need it.
1st tip: Under the Apple Menu (At left on the menu bar at the top of screen), 1st item is 'About this Mac'. Tells you everything about your Mac, including OS.