In the ancient Greek seacoast town of Abdera, 25 centuries ago, philosophers Leucippus and Democritus were teaching that all matter is composed of empty space and indivisible bits of matter called atoms. What little is left of Abdera is now only ruins. None of the written works of Leucippus have been preserved over the millennia, and only a few tantalizing fragments of the writings of Democritus still exist today. However, their insight that all matter consists of atoms is, today, the foundation upon which modern chemistry is based. To understand the chemical structure and acid deterioration of paper, we need to know how atoms combine into molecules which make up paper fibers.