The ISOSCALAR Giant Dipole Resonance: A review

The current status of research on the Isoscalar Giant Dipole Resonances (IS GDR) is reviewed. Recent small-angle inelastic alpha scattering measurement s have provided the best evidence so far for this resonance. The most recen t data indicate that the ISGDR strength, rather than being concentrated in a "peak", is spread over a large excitation-energy range. The implications of the ISGDR results for nuclear incompressibility are discussed.