Synchrotron radiation: A continuing revolution in X-ray science-Diffraction limited storage rings and beyond

Electron spectroscopy and the investigation of the electronic properties of matter have been largely impacted by the development of synchrotron radiation sources providing highly brilliant, easily tunable X-ray beams with selectable polarization properties. In this brief review the development of synchrotron radiation sources over the last 50 years will be described and the scientific opportunities presented by ongoing and future source developments will be briefly highlighted.