What I really love about this book is how much Mr. Hemenway goes into the *reasons* that these methods work. Call me obsessive, but I like authors to provide a good reason their techniques work and not just say "OMG, look at this harvest, just do exactly what I do!" Mr. Hememway gives us beautiful, well-though out tables of different nutrients certain plants accumulate, what kinds of bugs they attract, plants that can tolerate drought or provide mulch on the spot, plants that have "spiky" roots that break up tough top-soil and plants that can provide structure or shade to other plants. It's about using the attributes of different vegetation to do the work for you in a way that doesn't adversely impact the land. Armed with this information, you can create your own "guilds" and areas of companion plants that work best for your location. Outside of a textbook, this is the most complete information on gardening I have ever come across. The author even presents the downsides of the methods in, what I feel, is a very even-handed manner. No one style fits every need and Mr. Hemenway addresses that. This is my favorite gardening book, period.