For those that, perhaps, were not interested in the last Field Guide (Paperless — a guide to how to maintain a paper-free office) but were looking forward to the promise of future Field Guides, this is sure to fulfill all your hearts's desires. The book starts slow, with only a few tips here or there that an experienced Mac geek doesn't already know, but it picks up from there. The last few chapters are especially useful. (My iBook copy is full of highlights and notes that I plan to go through and implement as soon as I have the time.)
The truth is that if you're a geek, you'll probably know some of the material covered in the book — if not most of it. But for those few, truly golden tips and tricks that you didn't already know, 60 Mountain Lion Tips is well worth the money.