There is an 8 page introduction that explains the reasoning and methods behind the books approach. The "Read Me" portion gives some great insight into just what this book is like. It begins, "This is a learning experience, not a reference book." and follows that up with seven main points. To summarize them, the book teaches what someone needs to know to get up and running. It is not exhaustive, it does not go over the history of the language. There are many finer points not addressed. Using multiple browsers would be helpful to the reader working through the book. Skipping activities will greatly reduce the value of the experience. There is quite a bit of redundancy, it is on purpose and beneficial. The examples are as slim as possible to focus on what matters and finally, not all exercises have definitive answers. If any of that turns your stomach, this really may not be for you.
The format does pretty much make reading straight through the book without working the exercises a waste of time. This was my biggest challenge with the book. If I wanted to read it I needed a pencil, my laptop, free time and somewhere I could work through at least a whole exercise at a time. This wasn't something I could fit in 20 minutes a night before bed. The authors recommend making it the last thing read before bed, but the end of my days are too busy to fit an exercise in. I found that a lunch hour, or a quiet week-end afternoon were my best opportunities for learning.
When I found those times, the book was thoroughly enjoyable. The humor was corny at times but almost always funny. I even chuckled out loud more than once. The exercises are widely varied as are the interspersed scenarios and stories that accompany the examples. I downloaded the necessary images for examples from the books web site though I avoided using downloaded code. It caused more errors due to typos, but I felt like I did better typing in the examples myself. I enjoyed working the cross-word puzzles and reading the 'interviews' with various pieces of technology. The time invested was much greater than for any other tech book covering similar ground, but I felt like the return justified the added time.
I think it is good to mention though, one last time, this is not a no-nonsense reference manual. In fact there is lots of non-sense and it is actually quite a bit of fun. But if the idea of 2 or 3 pages of big pictures to get across a couple simple ideas about data types bothers you, don't spend the money on this book. It will just annoy you and you will probably feel ripped off. On the other hand, if you've picked up hefty programming manuals and found that you didn't make it a quarter of the way through, and didn't remember much of the quarter you did finish, this approach may be much more friendly and give you a taste of success. And what good is a more information dense book if you don't read it or learn from it?
The table of contents gives a short summary of each chapter and a breakdown by section. The section titles are good for finding a place you read or stopped but wont always help find a topic. They are often named with the name of the exercise, not the subject they address. The index is good though and will help quickly track down topics. Like many new O'Reilly books, this one comes with 45 days free access to the electronic version of the book on Safari. The books site, linked above, has the table of contents, index, code examples and the complete second chapter available for viewing and/or download.