J.-P. CALISTE, A. TRUYOL AND J. WESTBROOK The Series, "Data and Knowledge in a Changing World", exemplifies CODATA's primary purpose of collecting, from widely different fields, a wealth of information on efficient exploitation of data for progress in science and technology and making that information available to scientists and engineers. A separate and complementary CODATA Reference Series will present Directories of compiled and evaluated data and Glossaries of data-related terms. The present book "Thermodynamic Modeling and Materials Data Engineering" discusses thermodynamic, structural, systemic and heuristic approaches to the modeling of complex materials behavior in condensed phases, both fluids and solids, in order to evaluate their potential applications. Itwas inspired by the Symposium on "Materials and Structural Properties" held during the 14th International CODATA Conference in Chambery, France. The quality of the contributions to this Symposium motivated us to present" a coherent book of interest to the field. Updated contributions inspired by Symposium discussions and selections from other CODATA workshops concerning material properties data and Computer Aided Design combine to highlight the complexity of material data issues on experimental, theoretical and simulation levels Articles were selected for their pertinence in three areas. Complex data leading to interesting developments and tools such as: • new developments in state equations and their applications, • prediction and validation of physical and energy data by group correlations for pure compounds, • modeling and prediction of mixture properties.