Recent experimental findings and theoretical approaches to the electric dipole (E1) strength distribution below the particle emission threshold at shell closures are revisited. Results from photon scattering experiments are discussed and compared to predictions within the quasiparticle--phonon nuclear model. An analysis of the fine structure of the E1 strength is presented. Recent studies of the E1 response of light exotic nuclei are also discussed.

PACS numbers: 23.20.Lv, 24.30.-v, 24.60.Lz, 25.20.-x