The identification of physicochemically meaningful, descriptive parameters that are correlated with catalyst performance is a key step for modelling and understanding heterogeneous catalysis and finding new and more efficient catalytically active materials. These parameters, which characterize the materials and the processes triggering, facilitating or hindering the reaction, might be called the materials genes of heterogeneous catalysis. These catalyst genes can be used to construct maps of catalysts, i.e., materials charts that highlight the small interesting regions of the (huge) space of all possible materials, where the search for highperformance catalysts should be focused.