Flooding is an increasingly important hazard in a world characterized by changing climate, particularly extreme weather events, urban encroachment on flood plains and the growing populations of coastal cities. This book argues that we need to have a fundamental rethink regarding the nature of flood risk, in which we move from viewing it as a problem that can be reconstructed using classical reductionist analysis, to one in which we see flood risk as fundamentally complex, and not just complicated, in the sense defined by current thinking regarding complexity. This new approach is applied to a range of crucial themes and issues, some of which extend beyond flood risk. These include evidence for changing flood risk from a range of regions and environments and an introduction to the basis of determining flood hazard and vulnerabilities. The author highlights links to environmental change, including climate change and human activities and puts forward alternative views as to what controls vulnerability to flooding. By applying complexity theory and the notion of tipping points to hazard and risk, he discusses whether or not complex phenomena, like flood risk, can be modelled and how through adaptation of everyday life we can improve resilience to catastrophic events.