I Hope it's Helpful
I'm actually going to take a short trip to an old gold field, so I wanted this as a reference. As stated by others, there is a lot of advertizing going on as you read through the book. I haven't felt as if it wasted my money, by any means. It remains to be seen whether it really is useful.

A good field guide
A good introduction to recreational gold panning and a quick read. It inspired me to buy a crevice tool and do some sniping which turned out pretty well for me the first time out! I would have liked a bit more on how to clean up black sand and or how to smelt/purify gold, but then I am a bit of a science geek.

Prospecting Gold 101
A real good entry level book with lots of good information on equipment, what to look for and how to start. A must read for all beginners!

Does what it says
I've been gold panning before a couple of times with my brother and, while I have found a little gold (and I do mean "little") thanks to his knowledge, I think our next outing will be more fruitful thanks to this book. The history of finding gold in California is also helpful since, as the author says, 75-85% of the gold remains undiscovered. I found the book helpful enough I'm planning on buying a copy for my brother.

Fun and informative!
Don't be fooled by the reviewer who (inadvertently?) gave this book zero stars. It is packed with great entry-level information on gold prospecting. Bravo Mr. Petralia!