Throughout history, militaries have made use of scientific and technical expertise to try to achieve 'operational advantage' in order to win wars, but technological developments since the industrial revolution have led to an exponential increase in the destructive power of weapons, with thermonuclear weapons able to kill millions (if not more) in a matter of hours. As civilian casualties in war have rapidly increased, some arms research has been diverted to try to develop 'precision weapons'. This talk critically examines these trends and argues that security-related science and technology need a shift in focus to understanding and tackling the roots of conflict, including resource and environmental problems. This, it is argued, will give a much better chance of creating a more secure future.