Adobe is a company... which sells MANY programs
What do you want to do, and what program do you plan to use?
For specific program questions, you should ask in the forum for that program
If you start at the Forums Index http://forums.adobe.com/index.jspa
You will be able to select a forum for the specific Adobe product(s) you use
Click the "down arrow" symbol on the right (where it says ALL FORUMS) to open the drop down list and scroll
The last CS version is CS6, CC is the next version after that and would probably have been called CS7 except Adobe changed the licensing model to subscription only, so decided to rename things. Both CS6 and CC are being sold but only CC is getting new features.
As far as what is “best” only you can answer that for yourself.
The older CS and the newer CC are collections of different versions of mostly the same products. You will probably find various books for the various products, so a book that talks about all products is unlikely to be in depth enough to teach a specific product, well. Again, what you find good, will be subjective depending on your interests and resources.
Here is one website’s summary about the differences of CS6 and CC—you can find others using Google: