Although the books say they can be used by someone who is new to Web site design, I think you need a little background before using these books. (I mean, what do the descriptions of XML or JavaScript mean if you don't already know what they are?)
The best features of these books are:
1) Tour of the Dreamweaver user interface. This is handy whether you are moving to a new version of Dreamweaver or have never used it before. You get a good introduction to all the basic features.
2) In-depth discussions of Dreamweaver features. Not only do you get the information on how to use Dreamweaver features, but also very complete discussions of why and when to use them. This is the kind of knowledgeable information you just don't get in a user manual from the manufacturer.
3) Tips and guidelines. Very useful hints on overcoming common problems. For example, a sidebar on overcoming line spacing difficulties gives four different workarounds for adjusting line spacing.
By the way, the author, Joe Lowery, has a reputation for being a great Dreamweaver resource, willing to help with technical problems and a very nice guy. His Web site has lots of links to Dreamweaver sites: http://www.idest.com/dreamweaver/. However, it looks like the site has not been updated in a while, so I hope he is not out of the business.