Roy Burdon discusses how our genes work, how they are adversely effected by a huge range of factors - toxic industrial and agricultural chemicals, excessive sunlight, nuclear radiation from power plants and the military, other forms of radiation, food contaminants, and atmospheric pollutants - and how they may be affected by genetic engineering. Burdon explains how the body defends itself from external attack, what happens when these defences are overwhelmed, and what humanity needs to do to develop a much more careful approach to new technologies, industrial processes, and food production.