There is increasing military interest in the development of techniques that can survey and possibly manipulate the mental processes of potential enemies, or enhance the potential of one's own troops. There is nothing new about such an interest. In the US, it stretches back at least half a century. Impressed by claims that the Soviet Union was developing psychological warfare, the CIA and the Defence Advanced Projects Agency (Darpa) began their own programmes. Early experiments included the clandestine feeding of LSD to their own operatives and attempts at 'brain-washing'. By the 1960s, Darpa, along with the US Navy, was funding almost all US research into 'artificial intelligence', in order to develop methods and technologies for the 'automated battlefield' and the 'intelligent soldier'. Contracts were let and patents taken out on techniques aimed at recording signals from the brains of enemy personnel at a distance, in order to 'read their minds'. These efforts have burgeoned in the aftermath of the so-called 'war on terror'. The step beyond reading thoughts is to attempt to control them directly. A new technique - transcranial magnetic stimulation (TMS) - has begun to generate interest. This focuses an intense magnetic field on specific brain regions, and has been shown to affect thoughts, perceptions and behaviour.