The aim of this publication is the understanding of large floods and their impact on the Earths surface. The major objectives are: 1) to take a second look at what constitutes a megaflood that the principle of uniformitarianism is at some loss to explain and 2) to try to determine what could happen in such large floods by analyzing those that occur in front of glaciers, in alluvial-fans and in alluvial valleys. The products of these floods are presented in terms of sedimentary deposits, erosional features and damage to human activities. The volume bears out the concept that sedimentological analysis can be a powerful tool, not only for reconstructing processes that have acted on ancient landscapes, but also as a technique for risk assessment of certain troubled areas. Therefore, this volume is of interest not only to sedimentologists/gemorphlogists, but also to engineers, landuse planners and anyone interested in the interrelation between humans and the environment. If you are a member of the International Association of Sedimentologists, for purchasing details, please see: http://www.iasnet.org/publications/details.asp?code=SP32