Microsoft Office SharePoint Designer 2007 is a reworking of Microsoft's older FrontPage product, customized to work with SharePoint.
It is a difficult tool to describe because several disciplines must be learned to master it and, more importantly, there are so many different uses to which it can be put.
"Microsoft Office SharePoint Designer 2007" is an attempt to put everything one needs to know in one place. It sort of succeeds and sort of doesn't.
It provides a somewhat superficial overview of designing for the web immediately after an even more superficial overview of server technologies. Quite honestly, if you don't have a background in both these subjects, this book will not help you. It is more a review tool than a teaching tool.
The rest of the book follows the same path: lots of subjects, with none of them covered in any real depth.
This might be useful as a lightweight reference, but for the SharePoint beginner and the experienced user, it simply doesn't cut the mustard. That is not so much the fault of the author, whose style is good, but of the too broad scope of the book.
Jerry