Earth, air, fire, water - it's all chemistry. Chemical reactions are agents of change, in the environment, in our bodies, our brains - everywhere. Chemists apply what they have learned from natural substances and reactions to invent synthetic chemicals for use as drugs, plastics, fabrics and much more. Our knowldge of chemistry can both harm us and help us. We use chemistry to understand and cure disease and to invent technologies that help sustain modern life. However, it also helps to create such problems as pollution. This book provides information about chemistry and how it is central to almost everything that happens.