<DIV>The three-dimensional aspects of molecular shape can be crucial to both properties and reactions. The Third Dimension explores the arrangements of atoms in molecules and in different types of solids. Initial chapters describe the common crystal structures and how they are related to close-packed arrangements of ions. Metallic, ionic, molecular and extended covalent crystals are covered; major types of crystal defects are also discussed. The book then introduces isomerism, and explores the stereochemical consequences of the tetrahedral carbon atom. Chirality is also investigated. The book concludes with a Case Study on Liquid Crystals, which describes structures, properties and applications. As visualisation in 3D is an important part of this book, the accompanying CD-ROMs provide video material, interactive questions and exercises using models to aid understanding of crystals, organic molecules and stereochemistry. All necessary programs are provided. The Molecular World series provides an integrated introduction to all branches of chemistry for both students wishing to specialise and those wishing to gain a broad understanding of chemistry and its relevance to the everyday world and to other areas of science. The books, with their Case Studies and accompanying multi-media interactive CD-ROMs, will also provide valuable resource material for teachers and lecturers. (The CD-ROMs are designed for use on a PC running Windows 95, 98, ME or 2000.)</div>