Based on these precepts, conceptual DFT has introduced a number of molecular reactivity descriptors, mostly response functions or descriptors derived from the E(N) curve, that -either alone or in combination with the electronegativityequalization principle, the hard/soft-acid/base principle, the maximum-hardness principle, or the minimum-electrophilicity principle, for example -have served as valuable tools for the interpretation of experimental and theoretical (computational) data for a wide variety of reactions. Its scope comprises "generalized" acid-base, complexation and redox reactions and a multitude of "classical" organic reaction types including pericyclic reactions, with substrates varying from inorganic to organic and organometallic molecules, to polymers and the solid state. The success of conceptual DFT in pervading a broad range of chemical subdisciplines -from inorganic, organic, and organometallic chemistry to biochemistry and materials chemistry -can be described as getting "insight from numbers", experimental or theoretical.