I've been recommending this book to new users of Lightroom 4 well in advance of the publication date, just based on my experience with the author's earlier Lightroom books. Happily, Scott Kelby did not make a liar of me.
The Lightroom 4 book follows just about the sequence that one would follow in using Lightroom, starting with importing images and organizing them in the Library Module. Editing has been expanded to three chapters and explains how to use the revised basic sliders in Lightroom 4. There are chapters on exporting, jumping to Photoshop and the output functions including printing, slideshow and the new book module. (The web module chapter has been dropped but is available on line.) The book finishes with some downloadable layouts and a step-by-step walk through the processing of a portrait.
The teaching technique is excellent for beginners. The various functions are broken down into simple steps of 2, 4 or more pages. There is a narrative of the steps to follow down the outside of each page with screen captures on the inside. The captures are necessarily small but large enough to read easily. You can download images from the book's website to follow along on your computer and I'd recommend doing so if you are just a beginner. I've followed along with several of these tutorials and they all seem to be accurately constructed with all the steps clearly spelled out.
The book is designed for beginners and not aimed at experienced users. Still, if an old hand knows what the new features are in Lightroom 4, it's easy enough to find just the chapter or section you want and follow along with the author.
The book certainly has benefited from its various iterations. Where tools have been carried over from older versions, everything is crystal clear. For a new module, like the book module, the instructions are still good, but they lack the complete clarity and smoothness of the other lessons. (If you've never done a book before, you may also want to go to the Blurb website which has a lot of good information. I continue to use Blurb's software because I can't figure out how to soft proof for Blurb in Lightroom.)