Layered or two-dimensional (2D) compounds have recently attracted the attention of the scientific community due to their potential industrial applications. Their importance lies on the possibility of controlling and modifying the interlayer space in order to confer different chemical properties to the 2D assemblies. Modifications can be carried out by exfoliation/intercalation, anion exchange and/or layer surface grafting reactions. The structure of the layered hydroxide salts (LHS) derives from the brucite-like structure, where a fraction of the structural hydroxide groups is replaced by water molecules and anions, resulting in compounds formulated as M(OH)(2-x)(A(m-))(x/m).nH(2)O. This paper describes the synthesis, characterization, properties and possible applications of this fascinating class of compounds. (c) 2007 Elsevier B.V. All rights reserved.