AGN VARIABILITY ACROSS THE ELECTROMAGNETIC SPECTRUM
One of the proeminent features of active galactic nuclei (AGN) is their strong luminosity variability from radio wavelengths up to the most energetic γ-rays. The progress in the characterization and the understanding of γ-ray variability in AGN observations by space- and ground-based telescopes is shortly reviewed, as well as the relationship between the two spectral continua they define.