The word "catastrophe" is used to signify a brutal event bringing large-scale death and destruction. In that sense, every armed conflict, every natural or technological disaster is a catastrophe. The present issue of the Review looks in particular at the threat of a nuclear, radiological, biological or chemical (NRBC) event. It further discusses the chance of mitigating a catastrophic event by developing emergency preparedness plans and the appropriate response capacity. As local capacities may often be insufficient to deal with a major crisis, international assistance is frequently required. As for NRBC weapons it is especially important to stimulate discussion on how governments can, perhaps together, counter these threats while they still remain hypothetical.