Static and dynamic wetting of solid surfaces by liquids is a focus of numerous theoretical, computational and experimental investigations. Most of the research and training activities are focused on the wetting of simple solids by one-component liquids. However, a wide variety of industrial processes mostly include wetting/spreading of complex multiphase liquids over heterogeneous, structured or (nano)porous solids. The latter include deposition of active substances from foams and nanoemulsions on human hair and skin and deposition of functional nanoparticles on textile fibers and flexible polymer films. The mechanisms of those complex fluid-solid processes are to be understood. The development and optimization of the industrial processes and products is based on purely empirical trial and error methods.CoWet supra-disciplinary project is aimed at bridging the gap between the industrially relevant processes involving the complex fluid-solid processes, from one side, and the high resolution experiment, as well as physically sound modelling and direct computer simulations, from the other side. The high-resolution, high-speed experimental techniques, including confocal microscopy, atomic force microscopy and fluorescent correlation spectroscopy, will be used to reveal the nano- and microscopic phenomena governing the complex fluid-solid interactions in the course of wetting/spreading processes of complex liquids over complex substrates. The modern computational and modelling techniques will help to reveal, predict and optimize the industry-relevant processes.The young researchers will be trained to study the systems of practical importance rather than focusing on model systems only. They learn the cutting edge scientific methodology and application technology from an industrial perspective. CoWet fellows will form a powerful network of experts which will eventually result in ground-breaking development of new complex fluid-solid technological processes.