This volume contains the proceedings of the Fifth International Conference on the Micromechanics of Granular Media, Powders and Grains 2005. Powders and Grains is an international scientific conference held every 4 years that brings together engineers and physicists interested in the micromechanics of granular media.The book is a guide to the hottest topics in the general problem of the microscopic description and understanding of granulates. Powders and Grains offer an excellent overview of the state of the art research on granular media. Authors from all over the world and different backgrounds discuss their most up-to-date research interests and results in more than 280 concise articles. Included are experimental, numerical, and theoretical investigations by both engineers and physicists. The result is a valuable tool for engineers, physicists as well as for applied mathematicians, geologists, and other scientists concerned with problems ranging from the most basic and theoretical, to the daily problems of industry production, process performance or construction design.