World leaders at the third Nuclear Security Summit in the Netherlands in March 2014 can point to measurable progress toward the goal of reducing and securing the materials needed to build a nuclear bomb. Seven more states have removed all or most of these dangerous materials from their territories since the beginning of 2012; more than a dozen others have taken important new steps to reduce quantities and to better secure the materials they hold. That progress in securing weapons-usable nuclear materials is measured here in the second edition of the NTI Nuclear Materials Security Index.