The most successful practical incarnation of this idea has been based on another highly successful idea -namely, that of rangeseparated hybrid functionals. These functionals can exhibit an asymptotically correct long-range (free or screened 505 ) Coulomb potential, while retaining a useful balance between exchange and correlation in the short range. The range-separation parameter is then tuned, per system, by enforcing the ionizationpotential theorem (or variants thereof). The approach has been successful in overcoming issues considered very challenging for DFAs, notably the infamous band-gap problem 506,507 and the prediction of charge-transfer excitation energies, through systematic elimination of derivative discontinuity errors. Importantly, this approach restores the physical picture of singleand two-quasi-particle excitation thresholds, by reliably predicting them from the HOMO-LUMO eigenvalue difference of a DFT calculation and the lowest eigenvalue of a TDDFT calculation, respectively, using the same exchange-correlation functional . Extensions of these ideas can be expected to continue to play a role in DFT applications to spectroscopy.