The nuclear crisis in Fukushima and growing threats of nuclear terrorism must serve as a wake-up call, prompting greater action to prepare ourselves for nuclear and radiological disasters.Our strategy to prepare for these threats is multi-layered and the events of these past years have proved the necessity to re-evaluate the national and international preparedness goals on a scale never before considered.The programme of NATO Advanced Research Workshop on "Preparedness for Nuclear and Radiological Threats" has been focused on science and technology challenges associated with our need to improve the national and international capacity and capability to prevent, protect against, mitigate the effects of, respond to, and recover from the nuclear and radiological disasters, including nuclear and radiological accident, terrorist attack by Improvised Nuclear Device (IND) or by "Dirty Bomb"-Radiological Dispersal Device (RDD), that pose the greatest risk to the national and international security and safety.