An overview of the progress in polymer nanocomposites is presented in this paper with an emphasis on the different methods used for preparing polymer-layered silicate (PLS) nanocomposites and the extent to which properties are enhanced. Other related areas that are also discussed include the types of polymers used in PLS nanocomposites preparation, the types of PLS nanocomposites morphologies that are most commonly achieved, the structure and properties of layered silicates, and the most common techniques used for characterizing these nanocomposites. (c) 2007 Wiley Periodicals, Inc.