Depends on what you want to do with it. If you want to create a permaculture landscape in your own yard and you know how to garden at least somewhat, use books and supplement them with your own gardening knowledge. There are lots of them out there, and you can get them for free from the library if you don't want to buy them. If you want to put in fruit and nut trees and haven't planted trees before, take a look at something like the American Horticultural Society's book on plant propagation or The Backyard Orchardist.