Parkinson disease (PD) is a common neurodegenerative condition. Typically beginning in the sixth or seventh decade of life, it is characterized by the unilateral onset of resting tremor in combination with varying degrees of rigidity and bradykinesia. PD was originally described by James Parkinson (1755-1824), a man of many talents and interests. Parkinson published works on chemistry, paleontology, and other diverse topics. Early in his career he was a social activist championing the rights of the disenfranchised and poor. His efforts in this area were enough to result in his arrest and appearance before the Privy Council in London on at least one occasion. In collaboration with his son, who was a surgeon, he also offered the first description in the English language of a ruptured appendix. His small but famous publication, "Essay on the Shaking Palsy," was published in 1817, seven years before his death. The clinical descriptions of 6 cases was remarkable in part because he never actually examined the people he described. Instead, he had simply observed these people on the streets of London.