This book is dedicated to two of the most important issues in agriculture: cover crops and crop yield. A cover crop is a crop planted in a garden to protect the soil from erosion and to improve the soil by adding organic matter. In agriculture, crop yield (also kwn as agricultural output ) is t only a measure of the yield of cereal per unit area of land under cultivation, it is also the seed generation of the plant itself, i.e. one grain of wheat produces a stalk yielding three grain, or 1:3. This book reviews the effect of cover crops and how the latter might lead to the improved soil and environmental quality if crop yields are sustained.