Welcome at HCM, the Hausdorff Center for Mathematics, a Cluster of Excellence established 2006 at the University of Bonn under the title "Mathematics: Foundations, Models, Applications" within the Excellence Initiative by the German federal and state governments. It has been successfully renewed for a second funding period in 2012. Its work thematically comprises a broad spectrum of mathematics as well as mathematical economics: from topics from the classical core areas of mathematics through mathematical modeling and numerical simulation in the natural and social sciences to industrial applications in chip design.