Single-IonMicrobeam(SIM)isuniquelycapableofpreciselydeliveringapredefinednumberofchargedparticles(precisedosesofradiation)toinpidualcellsorsub-cellulartargetsinsitu.Sincetheearly1990's,therehasbeenanever-increasinginterestindevelopingandapplyingtheSIMtechniquetoproblemsinradiobiologyforstudiesofcellandtissuedamagedbyionizingradiations.PotentialapplicationsforSIMinradiobiologycontinuestogrowandhavebeenpersified.Therearecurrentlymorethan14SIMfacilitiesworldwide,andtheyhavebeeninaconstantstateofevolution.ThispaperreviewsthecurrentstateofSIMresearchworldwideandtherelatedpivotaltechnologicaldevelopmentsinthefieldsofbothbiophysicsandradiobiology.RepresentativeapplicationsandtheperspectiveofSIMarealsointroducedanddiscussed.