Prof. Dr. Demetris Koutsoyiannis is a Professor Emeritus of Hydrology and Analysis of Hydrosystems at the National Technical University of Athens. He received his Ph.D. in Hydrological Stochastics from the National Technical University of Athens in 1988. He has served as a Professor of Hydraulics at the Hellenic Army’s Postgraduate School of Technical Education of Officers Engineers (Athens, 2007–2010). He has been a visiting academic/professor at the Imperial College (London, 1999–2000), Hydrologic Research Center (San Diego, 2005), Georgia Institute of Technology (Atlanta, 2005–2006), University of Bologna (2006 and 2019) and Sapienza University of Rome (2008 and 2019). He has been awarded the International Hydrology Prize—Dooge medal (2014) by the International Association of Hydrological Sciences (IAHS), UNESCO and World Meteorological Organization (WMO), and the Henry Darcy Medal (2009) by the European Geosciences Union (EGU). He was the Editor of the Hydrological Sciences Journal for 12 years (2006–2018), and a member of the editorial boards of Hydrology and Earth System Sciences, Journal of Hydrology, Water Resources Research, Hydrology and Sci. His research interests mainly include civil engineering, water resources engineering, hydrology, stochastics, and climatology.