Prof. Arnold Verruijt is Emeritus Professor of Soil Mechanics at Delft University of Technology, the Netherlands. He received his MSc and PhD degrees in 1964 and 1969 from this university. He stayed with the university until he retired in 2002, interrupted by Visitor Professorships at Ontario (Canada), Haifa (Israel) and Sydney (Australia). He has published many papers and several books on groundwater flow and soil mechanics, usually with an emphasis on theoretical solutions of engineering problems. His main research interests are the development of analytical and numerical solution methods, such as the complex variable method and the finite element method. Prof. Verruijt is a member of the Royal Netherlands Academy of Science (KNAW) and an honorable member of the Royal Institute of Engineers (KIVI). In 1997, he was appointed Officer in the Order of Orange-Nassau by Queen Beatrix. At Delft University of Technology he was known as an excellent teacher, for which he received the (first) Master Prize of the Delft University Foundation. In 2014, he received the Biot medal of the American Society of Civil Engineers (ASCE) for his pioneering contributions to the theory of poroelasticity. He also acted as consultant on engineering projects, such as tunnels, river embankments and storm surge barriers, mainly in the Netherlands but also abroad.