I've been an intermediate Flash guy for years. The simplicity of ActionScript 1 and 2 made them easy to grasp for all the basics, but the limitations were also abundantly clear.
When ActionScript 3 debuted, I was excited that it had finally become a "real" programming language. But despite being a programmer since before there was an Internet, I found much of ActionScript 3 to be confusing, and honestly, intimidating.
I tried doing it on my own, and I tried other books. But they were either too focused on the language itself and lacked context for the sorts of real-world tasks one does in Flash, or they didn't go deeply enough. ActionScript 3.0 Visual Quickstart Guide finally struck the right balance -- at least for me, and my learning style.
As a programmer, I didn't need to be spoon-fed the basics of variables and control structures. But as a UI guy, I also needed practical, real-world examples like working with dynamic text, interfacing with the outside world, and loading assets.
Quite literally within minutes, I was able to use the straightforward, clear examples and explanations to whip-out Flash movies with ActionScript 3.0 handling the heavy lifting, and finally achieve some things I'd be struggling for months to learn through searching for code examples found online.
Two things are clear from reading the book, however:
1. While the book does cover the basics, people completely new to programming are probably going to be more lost than anything. This is a small book, and the content is relatively brief. If you want your hand held from a standing non-programmer start all the way to ActionScript expert, this probably is not your book. You should understand what programming is, and basic concepts (like variables and control) before you start. This book will help you connect that knowledge to ActionScript 3.
2. You're not going to become the world ActionScript 3 expert by reading this book. You'll get a superb foundation that will give the typical Flash designer/programmer everything they need, and a range of core knowledge that you can augment with some of the "deeper" books, web searches, or just plain reading the Flash manual. But I suspect that most readers, like me, will come out of this book with the stuff you really need for most real-world Flash work.
In summary, the book is well planned out, well written, and the examples -- every single one I tried -- worked as written, free of the typos, errors and omissions that seem to plague other ActionScript 3 books (based on reading reviews here at Amazon.com, anyway).
While your mileage may well vary, for me, for my learning style, and for someone of my experience level, this book was perfect, and finally (FINALLY!) the ActionScript 3 guide I was looking for.