Chemistry is considered by some to be the central science because the study of matter and its changes is fundamental to understanding all other sciences. For this reason, the study of chemistry is essential to the preparation for a profession in any scientific discipline or engineering field, medicine or pharmacy, even business or the social sciences. Without a doubt, the study of and care for living things has become focussed on the chemical substances and their reaction mechanisms. Perhaps less obvious is our growing dependence on the transformation of matter and energy which results in the products and processes that we take for granted as the basis of our modern standard of living.