If you've never used a computer before, this book should be perfect for you. If you've never used a Mac before, it will be very good. If you've used early Mac operating systems, but not OS X, it will still be quite good. If you already know earlier versions of OS X very well, you won't find a lot here to help you. There is no section that summarizes changes from earlier versions. There is no consistent identification of OS or app features that are new with Lion. This book is generally about OS X, and it is not an in-depth treatment. If you want in-depth, get the Portable Genius book (which was not out for Lion when I did this review). Most of the book's space is devoted to the apps included with the OS. There are some exceptions, such as the page on Mission Control, which is new to Lion. There is also a very nice treatment of file sharing and printer sharing. On the other hand, there's a whole page on how to save a document!
So why in the world did I give it four stars? Even though I've been working with computers, including software development, since the days when a single computer filled a small room, I'm relatively new to Macs. And this book does do a creditable job of an overview of the OS and the apps. Yes, it's very "Dick and Jane." You have to try not to be offended when it tells you things that any near-computer-illiterate would know. You have to scan each page looking for nuggets. The nuggets are there ... they really are. They are easy to find, because a huge amount of effort has gone into creating a good visual presentation. If you are not familiar with an app, you can go through the appropriate section of the book in just a few seconds and save yourself some trial and error.
In summary, the book is well organized and designed to make information easy to find and to absorb. If you're computer literate enough to be reading this review, I can't imagine how you could find anything in the book that would be too difficult for you. It is a simple book, but that is partly because the author does a good job of simplifying. The book falls right in line with Apple's own philosophy of simplicity. Even so, this is not necessarily a book for the simple.
All the best,