In recent years, silica aerogels have attracted increasingly more attention due to their extraordinary properties and their existing and potential applications in wide variety technological areas. Silica aerogel is a nanostructured material with high specific surface area, high porosity, low density, low dielectric constant and excellent heat insulation properties. Many research works have been carried out concerning aerogel production and characterization. In this review paper, research work and developments in synthesis, properties and characterization of silica aerogels will be addressed. Particular attention is paid to drying which is a critical step in aerogel synthesis and makes the production of this material more economical and commercial. (C) 2007 Elsevier B.V. All rights reserved.