The assessment of flood risk considers individual risk, economic risk and environmental risk yielding qualitative and quantitative statements which are typically subjected to substantial uncertainties. Flood risk assessment comprises hazard assessment and vulnerability assessment. In the frame of hazard assessment flood events are analysed by means of recurrence intervals and spatio-temporal flood characteristics. Within vulnerability assessment flood prone utilisations are typically characterised by stage damage functions or risk curves. The objective of the book is to revise flood risk assessment methodologies and to quantify inherent epistemic uncertainty emerging from different sources and processes. This work comprises scientific publications with emphasis on fundamental aspects of flood risk: (1) uncertainty analysis, (2) environmental flood risk assessment, (3) economic flood risk assessment and (4) individual flood risk assessment. Conclusions were drawn on the basis of specific case studies, mainly within the federal territory of Austria.