This volume includes 58 contributions to the 11^th International Conference on Surface and Colloid Science, a highly successful conference sponsored by the International Association of Colloid and Interface Scientists and held in Iguassu Falls, Brazil, in September 2003. Topics covered are the following: Biocolloids and Biological Applications, Charged Particles and Interfaces, Colloid Stability, Colloidal Dispersions, Environmental Colloidal Science, Interfaces and Adsorption, Nanostructures and Nanotechnology, Self-Assembly and Structured Fluids, Surfactants and Polymers, Technology and Applications, Colloids and Surfaces in Oil Production. Surface and colloid science has acquired great momentum during the past twenty years and this volume is a good display of new results and new directions in this important area.