After farming sheep and cattle in New Zealand, John Grrenfield worked in the tropical wet and arid zones of developing countries throughout the world for 40 years developing a system of soil and moisture conservation that would be sustainable in extremes of climate. The last 18 years were spent with the World Bank as Senior Agriculturist. In this period the author has seen how inappropriate the accepted constructed systems of conservation are and made it his mission to develop a simple sustainable system that is eco-friendly and affordable to the poorest of the poor subsistence farmers world wide.