  Ninety years of X-ray spectroscopy research in Italy, from the X-rays
discovery (1896), and the Fermi group theoretical research (1922-1938) to the
Synchrotron Radiation research in Frascati from 1963 to 1986 are here
summarized showing a coherent scientific evolution which has evolved into the
actual multidisciplinary research on complex phases of condensed matter with
synchrotron radiation.
