Liquid chromatography modelling represents a real challenge to understand the phenomena encountered in the separation process of biomolecules, especially in non-linear adsorption cases, and to enhance production rates and recovery yields in preparative chromatography. The three major ways to describe liquid chromatography are presented, i.e. the continuity equations, the theory of interferences and the plate theory. The former is described in detail, since it permits the inclusion of various physical and thermodynamical phenomena, and to handle non-linear adsorption problems. The numerical ways of solving the differential equations stated by the different models are also considered. The interference theory, despite its limitations to ideal situations, is still considered as a useful tool in non-linear multicomponents liquid chromatography modelling. The plate theory is not developed, for it is restricted to linear adsorption cases.