Around AD 105, a quiet court official in China changed the course of history. His name was Cai Lun, a servant in the imperial palace during the Han Dynasty. The empire kept records on heavy bamboo strips or expensive silk cloth. Bamboo tablets filled carts. Silk cost a fortune.
Cai Lun searched for something better. He gathered tree bark, worn rags, old fishing nets, and scraps of cloth. He crushed the fibers, soaked them in water, and pressed the pulp into thin sheets. When the sheets dried...