Mulliken's early work on the magnitudes of charge-transfer transition moments and on their nuclear-coordinate dependences is of fundamental importance for an understanding of the magnitudes, anisotropies and nuclear-coordinate dependences of molecular polarizabilities and hence of dispersive intermolecular interactions. His prediction of large two-electron charge-resonance transition moments between excited states of ionic character at large internuclear distances is consistent with detailed ab initio results for the hydrogen molecule in which the interaction between ionic and excited neutral configurations generates interesting additional structures in the pattern of electronic energy curves and transition moments.