A more complete and, crucially, predictive view of organic crystal packing can be obtained from crystal structure prediction (CSP) . A core concept in CSP is the crystal energy landscape (or CSP landscape) -the set of plausible crystal packings for a chemical species (or combination thereof), representing an exploration of the crystalline configuration space to identify candidate structures predicted to be stable (which ideally includes any observed structures), ranked in terms of this stability. These CSP landscapes are of great utility in understanding and rationalising the thermodynamic and kinetic behaviour of crystal systems; multiple lowenergy minima that are close-lying on a CSP landscape may be indicative of a significant risk of polymorphism, while dynamical simulations exploring these landscapes give insight into the kinetic trapping of metastable forms and the observed absence of other predicted forms .