I would say this is less a frugal living book and more a frugal living encyclopedia, which is to say there is a little information about a lot of topics. In fact, there was so much that I feel like I couldn't really get the full benefit of the book having checked it out from the library so I might need to get a copy of it for myself. I think some readers might complain about the lack of depth, but I feel like that's really unachievable unless you wanted a truly encyclopedia sized set. That being said, the index of the book contains a list of all the source materials they used for the book so if you want more depth on a specific topic, you can easily find a book dedicated to just that one thing.
In the realm of frugal living, the book seems to focus primarily on Do It Yourself activities. It includes everything from maintaining your home and car to cutting your own hair (or your family's hair). It even includes a section on knitting, though it claims it's not a frugal activity, which I have to disagree with. You might be able to buy a sweater at a thrift store for $8, but when you make it yourself you can use more elaborate patterns (which you can get for free) as well as better quality materials and construction. Plus, if you think of knitting as entertainment, the number of hours you can spend making even a small item means that your hobby comes out to pennies-per-hour in fun.
I think the benefit of this book is that it does give a lot of options for costs savings, so the reader can pick and choose which activities apply to their lifestyles, range of skills, and willingness to be radically frugal. Then they can do further research on the topic to really improve their cost of living without reducing their quality of living.