The paper presents an innovative approach to detect and visualize non-covalent interactions in molecular systems, which are crucial for understanding biological processes and designing new materials and drugs. The method relies on the electron density and its derivatives, specifically the reduced density gradient, to identify regions of low density and low reduced gradient, which are indicative of non-covalent interactions. This approach complements existing methods for covalent and electrostatic interactions and provides a rich representation of van der Waals interactions, hydrogen bonds, and steric repulsion. The method is efficient and applicable to large systems, including proteins and DNA, by using approximate promolecular densities. The authors demonstrate the effectiveness of their method through various examples, including small molecules, molecular complexes, and solid-state systems, showing that it can accurately map and visualize non-covalent interactions as continuous surfaces rather than simple atom pairs. This tool offers significant insights into the design of ligands, self-assembled materials, and catalysts.The paper presents an innovative approach to detect and visualize non-covalent interactions in molecular systems, which are crucial for understanding biological processes and designing new materials and drugs. The method relies on the electron density and its derivatives, specifically the reduced density gradient, to identify regions of low density and low reduced gradient, which are indicative of non-covalent interactions. This approach complements existing methods for covalent and electrostatic interactions and provides a rich representation of van der Waals interactions, hydrogen bonds, and steric repulsion. The method is efficient and applicable to large systems, including proteins and DNA, by using approximate promolecular densities. The authors demonstrate the effectiveness of their method through various examples, including small molecules, molecular complexes, and solid-state systems, showing that it can accurately map and visualize non-covalent interactions as continuous surfaces rather than simple atom pairs. This tool offers significant insights into the design of ligands, self-assembled materials, and catalysts.