Jack van Wijk is full professor in visualization at the Department of Mathematics and Computer Science of Eindhoven University of Technology (TU/e). His current research interests are information visualization and visual analytics. Previously he worked on flow visualization and mathematical visualization. The challenges are enabling people to explore and understand large amounts of abstract data (information visualization) and integrating methods and techniques from statistics, machine learning, and data mining to deal with even larger data sets (visual analytics). Van Wijk’s work spans many aspects of visualization - representation, interaction, evaluation, and methodology - for a wide variety of applications and data types. He is known for his work on hierarchical data and network visualization. With his students, he has developed new techniques for treemaps, exploring large image collections, event data, vessel traffic, and medicine prescriptions. His current focus is on visually explaining the results of automated methods. Useful results have been obtained for dealing with decision trees and models for judging vessel behavior, the next aim is to develop more generic methods.