The exploitation for peaceful purposes of nuclear knowledge and nuclear technology is inevitably connected to the exploitation of the same phenomena for military purposes. Moreover, many of the key processes that are at the heart of the civilian nuclear industry (particularly, enrichment and reprocessing of spent fuel) are at the heart of a weapons production programme. If the problem is not to be disposed of by outlawing nuclear activities for any purpose, then the critical vulnerabilities of peaceful operations need to be identified and measures need to be adopted that offer the greatest assurance that such operations are not misused to produce weapons of any kind.