Structural crystallographic studies can determine not only the full stereochemistry of chemical species but also their details of arrangement in the crystal. Such geometrical data provide an essential basis for the interpretation of chemical, physical, and biological properties of chemical species. This volume contains key papers presented at the seventh symposium on organic crystal chemistry at Poznan in Poland. Among the themes discussed were factors influencing molecular conformation and polymorphism, chemical and biological activity, intermolecular interactions, crystal chemistry of polymers and molecular modelling.