The importance of clay minerals and their origin is crucial to an understanding of the physico-chemical functions of the interface at the Earth soil interface. Clays are the product of slow transformations of high temperature rocks into reactive, fine grained material. This material, once in the sphere of plant interaction, becomes highly reactive with transformation periods of tens to hundreds of years. The challenge of the future is to use these rapid responses to the benefit of mankind. This book aims to further a better understanding of such mechanisms, and it is thus destined for an audience of ecologists, pedologists, agronomists and other researchers involved in earth surface science