I Introduction.- Aerogels - a Fascinating Class of High-Performance Porous Solids.- II Production and General Aspects.- Aerogels of Inorganic Oxides.- Advances in Production of Transparent Silica Aerogels for Window Glazings.- Large-Scale Production of Airglass.- Aerogels: Precursors or End Materials?.- The Sol-Gel Process for Non-Metallic Inorganic Materials.- Synthesis and Structure of Borate Based Aerogels.- Preparation, Densification and Characterization of Autoclave Dried SiO2 Gels.- Microporous Silica Fibres.- III Energy Conservation and Thermal Properties.- Translucent Insulation for Passive Solar Energy Utilization in Buildings.- Thermal Transport in Porous Superinsulations.- Thermal Conductivity of SiO2-Aerogel Tiles.- Radiative Heat Transfer in Silica Aerogel.- Thermal Conductivity of Granular SiO2 Aerogel.- Thermal Properties of Silica Aerogel.- Solar Transmission of Aerogel Pellets.- Aerogel as a Transparent Thermal Insulation Material for Buildings.- IV Structural Aspects.- Microstructural Properties of Transparent Silica Aerogels.- Pore Size Distribution of Silica Systems.- Microstructure of Silica Based Aerogel Using High Resolution Transmission Electron Microscopy.- Structural Analysis of Granular Silica Aerogels.- Mechanical and Acoustic Properties of Silica Aerogel.- V Applications.- Aerogel in High Energy Physics.- Silica Aerogel and Space Astrophysics.- On Some Recent Applications of Aerogels.- Index of Contributors.