  The KLOE experiment at the $\phi-factory$ DA$\Phi$NE in Frascati is the first
to have employed Initial State Radiation (ISR) to precisely determine the
$e^+e^-\to\pi^+\pi^-(\gamma)$ cross section below 1 GeV. Such a measurement is
particularly important to test the Standard Model (SM) calculation for the
$(g-2)$ of the muon, where a long standing 3$\sigma$ discrepancy is observed. I
will review the ISR activity in KLOE in the last 18 years from the measurement
of the hadronic cross section to the first direct determination of the
time-like complex running $\alpha(s)$ in the region below 1 GeV.
