I recently purchased this book and I've come to believe that the value of it depends on everyone's own gardening needs and level of expertise.
This book covers lots of topics in it's short 155 pages. Everything from climate, topography, garden style, basic botany, soil preparation, weeding, propagating herbs, drying herbs, cooking with herbs, medicinal uses for herbs, all the way to ending with a USDA Hardiness map. 155 pages doesn't lend room to cover any of those topics completely, but it does touch the surface and give the basic information necessary, which is all that most home gardeners are wanting or needing.
If you are a beginner gardener, this would be a great book for you. While it may be overwhelming on your first time through, it will begin to come together for you as you gain more insight to herb gardening.
However, if you are a more experienced gardener, looking for more in depth information on certain herbs, then this isn't the book you're looking for.