We are developing various computational methods to predict the thermodynamically feasible crystal structures of organic molecules. This is aimed at designing new molecular materials, and predicting polymorphism, the ability of a molecule to adopt more than one crystal structure, as an aid to pharmaceutical development. The develop of a computational method of crystal structure prediction (CSP) is done in close collaboration with Profs Adijman and Pantelides whose codes CrystalPredictor and CrystalOptimizer are used. The interpretation of the CSP output is done by collaboration with various experimental groups. The Control and Prediction of the Organic Solid State (CPOSS) Project web-site www.cposs.org.uk gives more details.