In late 1916, while treating a group of patients at his psychiatric clinic at the University of Vienna, Dr. Constantin von Economo began noticing the appearance of strange symptoms that he could not account for. At the same time, in France, Rene Cruchet began noticing similarly strange and unexpected symptoms in his patients. Though the two men had never met and knew nothing of one another’s patients, they would come to learn they were both witnessing the emergence of a new mysterious disease that would soon affect millions of people around the world. The illnesses documented by von Economo and Cruchet would eventually come to be know as encephalitis lethargica, or sleeping sickness, a strange condition that caused profound lethargy, hypersomnia, and a wide range of other frightening symptoms. Between 1919 and the early 1930s, millions of people all around the world contracted the illness, with nearly half of all cases resulting in death, and many more suffering long-term effects; yet a cause of the illness has never been established and the terrifying epidemic appears to have faded from memory not long after the disease itself ostensibly disappeared.