Land degradation from soil erosion has been considered by many to be a problem of significant proportion, affecting some 30–50% of the earth's land surface. At the time of the first publication of this book in 1993, estimates indicated that 10–15 million hectares of land were being lost each year through erosion and salinisation from irrigation and that at such a rate of loss, topsoil reserves on most sloping lands would be depleted within two hundred years. Since humankind's dependency on the land for food is almost total, soil erosion represents a real threat to the security of our food supply. The need for the immediate conservation of the world's soil resources is therefore clear. As part of the response to this need, the International Union for the Conservation of Nature's Commission on Ecology convened a special working group to consider the problem of world soil erosion and to propose practical solutions for soil conservation. This important book presents the outcome of their work.