Robert P.W. Duin received in 1978 the Ph.D. degree in applied physics from Delft University of Technology, Delft, The Netherlands, for a thesis on statistical pattern recognition. He is currently an Associate Professor in the Faculty of Electrical Engineering, Mathematics and Computer Science of the same university. During 1980-1990, he studied and developed hardware architectures and software configurations for interactive image analysis. After that he became involved with the design, evaluation, and application of algorithms that learn from examples, which includes neural network classifiers, support vector machines, classifier combining strategies, and one-class classifiers. Especially complexity issues and the learning behavior of trainable systems receive much interest. From 2000 he started to investigate alternative object representations for classification and he thereby became interested in dissimilarity-based pattern recognition, trainable similarities, and the handling of non-Euclidean data. Dr. Duin served as an associated editor of Pattern Recognition Letters and of the IEEE Transactions on Pattern Analysis and Machine Intelligence. He is a Fellow of the International Association for Pattern Recognition (IAPR). In August 2006 he was the recipient of the Pierre Devijver Award for his contributions to statistical pattern recognition. In 2011 he officially retired but he continues to work on some projects and maintaining and upgrading his software, in particular PRTools. He developped a special interest in the dependency of pattern recognition systems on the expert knowledge of its designers. Together with Elzbieta Pekalska he started a website, http://www.37steps.com, to document, explain and illustrate the use of software tools for pattern recognition.