Rien van de Weygaert received the PhD degree in astrophysics from Leiden University in 1991 on the role of cosmic voids in the large-scale mass distribution in the Universe. He is a professor of cosmic structure formation in the Kapteyn Astronomical Institute, University of Groningen. His research interests iclude cosmology, the large scale structure of the Universe, cosmic structure formation, galaxy formation and evolution, computational geometry and topology, and the history of astronomy.