This volume contains the proceedings of the IXth annual meeting of the European Colloid and Interface Society (ECIS) which took place in Barcelona, Spain, in September 1995. The contributions cover a broad range of fields in modern colloid science, as well as their technical, experimental and theoretical aspects. Specific emphasis is given to: - Surfactant aggregates, micelles, vesicles and liquid crystals; - Colloidal particles: interaction, structure and aggregation; - Emulsions and concentrated systems; - Microemulsions; - Mixed colloidal systems; - Rheology; - Biocolloids; - Membranes, films and interfaces.