With the growing recognition that many organic reactions may be conducted easily in the solid state and that organic solids may have unique optical/electronic properties, there has been much interest - in both academia and industry - in the subject of organic solid state chemistry. This book provides, for the first time, a coherent, unified view of the subject. It describes the packing of molecular crystals and how this packing influences chemical reactions in the solid state. It is concerned with various means of studying the chemistry and physics of molecules in constrained environments. Both experimental and theoretical approaches are discussed. Finally, it tackles the question of prediction of crystal packing, or crystal engineering'. The strength of the book lies in the twin approach adopted, namely that both conceptual and comprehensive chapters are present, in almost equal numbers.