Introduction

Chemistry is not confined to the laboratory -- it runs through the whole history of the Earth and of life on it. Over billions of years, natural processes such as rock weathering, volcanic eruptions, photosynthesis, the ripening of fruit, fermentation, and the release of fragrance by flowering plants have all been, at their core, chemical transformations. The same is true within the human body itself, where chemistry drives everyday physiological processes. Long before modern science existed, human civilisations across the world had already learned to put plant, animal and mineral products to practical use for health and daily life, purely from observation and experience. It was only with the advent of modern chemistry that scientists were able to work out the actual molecular structures behind these traditional uses, and synthetic organic chemistry then went further still -- both reproducing natural molecules artificially and creating entirely new molecules with modified structures, which have gone on to influence nearly every walk of human life, from food and clothing to shelter and beyond. This chapter narrows that huge canvas down to three everyday areas where simple-structured compounds do important chemical work: the chemistry behind the food we eat, the chemistry behind medicines that treat illness, and the chemistry behind the soaps and detergents that clean us and our surroundings.