I've been using Flash since Flash 3 or 4 (I can't remember)...and what I've learned has been all self-taught. My work has included Flash-to-SMIL presentations, Flash-to-Director CD-ROM applications, etc.
So...why buy this book? I feel that I'm an intermediate -- I know how to do a lot of things in Flash, but I'm not an "expert" or "certified" level Flash user. I think this book is great for beginners and intermediate users of Flash, as it's very detailed in its explanations of Flash tools/techniques. It also presents the subject matter in a relatively comprehensive, well-organized format.
Caveats to all of this include...
- some chapters barely touch on the samples in the CD-ROM
- some chapters are a bit extraneous
That last one is important -- there's a whole chapter on cartoon animation. While some of the principles in the chapter are essential for animators in general, I think a whole chapter devoted to cartoon animation is a bit much -- a topic for another book. Other "extraneous" chapters are OK, as they're more informative -- the project management chapter is a great example.
I gave this book 4 out of 5 stars because of these few things, but I can still highly recommend it.