Nature works and has been working for a billion and a half years-ever since there were living things on earth. This is important. We talk of controlling nature, but any wise farmer or stockman knows that nature makes the rules for us to learn and follow, if we can. In short, the ecologist is in a position to furnish us, in many ways, models which we can follow in our own operations. Before the prairies were settled, plowed and fenced, wild herds moved back and forth across them, never staying in one place after the grass was cropped too short. These moving herds distributed minerals from their droppings and remains, for it is well-known that wild animals usually maintain a good mineral balance by visiting salt-licks and varying their pasture-grounds. Here in a nutshell is the model for proper use of grasslands. It takes a lot of common sense to get across the information we need. He has it and can put it out so we can all understand it. (From the Introduction)