This　paper　demonstrates　the　utility　of　an　industrial　control　system　testbed　that　incorporates　a　universal,　realistic,　measurable,　controllable　and　reusable　experimental　platform　for　cyber　security　research　and　testing.　The　testbed　has　a　layered　architecture　that　leverages　physical　devices　and　emulation　and　simulation　technologies.　The　testbed　enables　researchers　to　create　experiments　of　varying　levels　of　fidelity　for　vulnerability　discovery,　product　evaluation　and　system　certification.　The　utility　of　the　testbed　is　demonstrated　via　a　case　study　involving　an　industrial　boiler　control　system.　©　IFIP　International　Federation　for　Information　Processing　2014.