Are artificial sweeteners dangerous for the body ? Can plastic packaging cause cancers by contaminating our food ? Could serious stomach complaints be caused by the nitrate contained in chemical fertilizer ? We have all heard the worrying stories about the danger posed by the numerous chemicals needed by industries to make the products which we use everyday. Does this mean there is good and bad chemistry ? The reader will find in this guide a great deal of surprising, and for the most part, reassuring information on the reality of the situation. John Emsley is a scientist at Imperial College, London. In addition to his regular radio slots, he writes for The Independent newspaper, and regularly contributes to New Scientist magazine.