Cai Lun is the man most often credited as the inventor of paper. Despite this incredible achievement (he is ranked as the seventh most influential person in history in The 100 by Michael H. Hart), he is little known in Western countries. In or around 105 A.D., Cai Lun, then a minor official in the Chinese imperial court, demonstrated his invention to Emperor Ho Ti. The emperor was pleased, and Cai Lun was rewarded with a promotion, an aristocratic title, and a great deal of wealth. He involved himself in politics, was somehow disgraced, and poisoned himself.

There is some question as to whether Cai Lun actually invented paper himself, as older Chinese paper fragments have recently been discovered. The Oxford Companion to the English Language entry on paper (one of the few reference materials available on the Internet that even refers to Cai Lun, and one that does so using the Wade-Giles spelling Ts'ai Lun) states that "about 200 BC, sheets were made from silk waste, then in AD 105 an official of the Imperial Court named Ts'ai Lun made a new kind of material from mulberry and other fibres, pieces of old fish net, hemp waste, and rags." Whether he independently discovered how to make paper or merely convinced his emperor to use it for imperial edicts, it is clear that he received credit for the invention in his day.

Aside from a brief synopsis of Cai Lun's life, there are few things known about him. Ancient Chinese records state that he was a eunuch. There is a story that, when he originally demonstrated paper to the Chinese people, Cai Lun was mocked, so he pretended to die and had himself buried in a coffin with a bamboo breathing tube. Following his instructions, his friends burned paper over the coffin, and he sprang up out of the ground, alive again. According to the story he did this to impress people with the magical power of paper. Burning paper over graves is still a tradition in China.