Reporting on advances in the field of molecular solid state chemistry, each volume focuses on selected areas and highlights methods and results in syntheses, properties and applications. The volumes in this series provide a forum for the discussion of chemical, physical, biological and crystallographic aspects of the molecular solid state. Eight chapters focus on the theoretical aspects of the reactivity of solids and the applications that are of practical importance. In a collection of reviews that highlight hot topics in the field of molecular solids, the authors of this volume emphasise the problems facing them. Contents: Interplay between Intra- and Intermolecular Interactions in Solid-State Reactions Cooperative Effects in Solid State Reactions Some Aspects of Bimolecular Photoreactions in Crystals Kinetics and Spatial Propagation of Intramolecular Reactions in Solids Kinetic Descriptions of the Simplest Bimolecular Reactions in Organic Solids Radical Solid-State Reactions at High Pressure Polymorphs and Solvates of Molecular Solids in the Pharmaceutical Industry Mechachemical Synthesis and Mechanical Activation of Drugs. Reactivity of Molecular Solids will be of interest to all chemists working in the pharmaceutical, fine chemicals and food industries, and also in molecular electronics and materials science.