Anyone who has ever dreamed of getting back to the soil will get from Maurice Grenville Kains' practical and easy-to-understand discussions a more complete view of what small-scale farming means. Most likely, you, like thousands of others who have read ''Five Acres and Independence,'' will come away with specfic projects that you can begin, specific plans that you can start to materialize. The farmer in you will begin to appear, bringing you closer to the fulfillment of that dream of independence on a small farm of your own.