Jan Karel Lenstra is CWI Fellow and former general director of Centrum Wiskunde & Informatica, the national research institute for mathematics and computer science in Amsterdam, the Netherlands. His research interests are in combinatorial optimization, in particular scheduling, routing, complexity, and approximation. He was co-editor of fifteen books, including "The Traveling Salesman Problem", "History of Mathematical Programming", and "Local Search in Combinatorial Optimization". He has been chair of the Mathematical Optimization Society and of the Royal Dutch Mathematical Society. He has also been chair of Committees on Mathematics in Primary Education and on Informatics in Secondary Education of the Royal Netherlands Academy for Arts and Sciences, and of the Spinoza and Stevin Prize Committees of the Dutch Science Council. He served as editor-in-chief of Mathematics of OR and of OR Letters. Jan Karel was awarded the EURO Gold Medal in 1997, and he became an INFORMS fellow in 2004. In 2011, he was made a knight of the Order of the Netherlands Lion.