Abstract: The present invention relates to a process for preparing mixture from a large number of components, the concentrations of the components used being capable of continuous variation over prescribed ranges in a very simple manner. For this, the mixtures are continuously prepared in a mixing assembly and continuously converted into a form which can be subjected to further processing. By way of example, the invention may be used for producing substance libraries for high-throughput screening in the plastics industry, in particular of mixtures of polymers with one another and of mixtures of polymers with added materials.