One of the major developments in Earth Sciences in general, and mineralogy in particular, has been the growth of our understanding of the microscopic behaviour of the complex materials that make up the Earth. This has been made possible by advances in our ability to probe minerals at the atomic level, over a large range of pressure and temperature conditions. New experimental techniques include the use of scanning probe microscopies to investigate mineral surfaces, as well as the use of neutron scattering, nuclear spectroscopies and synchrotron radiation to investigate the bonding and structure of minerals. In addition, there have been major developments in computational methods so that it is now possible to calculate the electronic structure of many rock forming materials. The aim of this volume is to give a coherent survey of the latest developments in experimental and theoretical approaches to the study of microscopic propertie~ and processes in minerals. Chapters in the book cover a number of key themes in the mineral sciences such as the behaviour of minerals at extremes of pressure and temperature, ordering in complex silicates, mechanisms of water incorporation in mantle phases, the importance of reactions occurring at the mineral surface, and the ability of computational methods to provide useful, qualitative information on the bulk and surface properties of minerals. The background to several experimental techniques is covered in some detail with examples of relevance to the issues cited above.