We are delighted to announce that Daan Frenkel, Professor of Chemistry at Cambridge University (UK), is the winner of the 2011-12 Joseph O. Hirschfelder Prize in Theoretical Chemistry. Professor Frenkel is well known for his pioneering theory and development of simulation methods, with applications to crystal nucleation, phase diagrams, and other problems. Professor Frenkel will visit the department during October 3-5, 2011, and will deliver three Hirschfelder Lectures during that period.