The usefulness of this book will depend in large part on how much experience the reader has with Apple computers in general. For those who are new to the ecosystem, it will probably be very helpful -- it covers a number of broad topics that apply to Apple computers in general, as well as the new features in Mountain Lion. But for confirmed Appleheads who want a bit of help with the latest version, this book is not that helpful -- at least it wasn't for me. Most of the book is stuff that I already know, the bits on new features in the software didn't create many "aha!" moments, and the hard questions don't even get noted. For that, I had to go to the on-line forums, and/or call Applecare. Everytime a new Apple product or big software upgrade comes out, I rush forth and buy a "For Dummies" guide. This is probably a conditioned response of the print-dependant. Maybe sometime I will get over it. ( )