Chris Klaassen was a distinguished statistician who earned his PhD under W.R. van Zwet in Leiden in 1980. He supervised 14 PhD students during his career. From 1990 until his retirement in 2014, he served as a professor at our institute. In addition to his academic articles, he became well known for the book Efficient and Adaptive Estimation for Semiparametric Models, co-authored with Peter Bickel, Ya'acov Ritov, and Jon Wellner.

He held several administrative positions within the faculty, including serving as Scientific Director of the KdVI. He also played an important role in the establishment of the Forensic Science and SFM master's programs. Chris was a beloved, dedicated, and warm colleague.