In this article, theoretical and experimental advances in the understanding of electronic processes underlying organic/metal (O/M) interface energetics are reviewed and correlated. The critical outlook comprises several key standpoints: (1) electronic basis of barrier formation at organic/metal interfaces, (2) dependence of organic/metal interface energetics on molecular conformation, (3) organic/ metal interfaces and charge injection in organic electronic devices, and (4) determination of the nature of O/M-bonded interactions using the electron density distribution. It is shown that, even in the case of weak interactions, the conformation of an organic molecule can be substantially changed upon adsorption on a metal surface, thus influencing the detailed understanding of organic/metal interfaces. Since interface energetics is essentially associated with a subtle balance amongst several mechanisms taking place at the metal-molecule contact and experiments usually detect only the cumulative effects of these mechanisms, experimental techniques and contemporary firstprinciple calculations are suggested to be combined in order to derive a comprehensive picture of the interfacial electronic structure. Because of the lack of satisfactory analytic theory for the elucidation of the dependence of charge injection on temperature, electric field, and energetic disorder in organic (opto-)electronic devices, some important experimental results are discussed. Our recently introduced general methodology for extrapolating the nature of interfacial interactions is herein elaborated by analyzing the topological features of the electron density at the organic/metal bond critical points determined by the quantum theory of atoms in molecules. The beauty is that the interfacial interactions are given physical definitions without invoking more traditional and non-invariant concepts, such as individual orbitals.