In the winter of 1933, rural Botetourt County, Virginia, residents were attacked by a phantom menace. An invisible gas filled the homes of unsuspecting victims, causing illness and resulting in a mass hysteria that reached the city of Roanoke. Despite best efforts of local law enforcement, the Mad Gasser somehow evaded capture. Who was this Mad Gasser? Was it simply a case of mass hysteria or was there a sinister attacker responsible for these unsolved crimes? For the first time, this mystery from Virginia's past is explored here, in detail, by historian William B. Van Huss. Go beyond the legend of the Mad Gasser; retrace the timeline of events, decipher the evidence, and explore the theories that have been proposed to explain this enigmatic cold case.