HelgaRoyston
NOT AHS Universe. The novel is based on the urban legend about Edward Mordrake, a Victorian nobleman born with the second face on the back of his head.
In sources the legend goes this way. "Edward Mordake (sometimes spelled Mordrake) is the apocryphal subject of an urban legend who was born in the 19th century as the heir to an English peerage with a face at the back of his head. According to legend, the face could whisper, laugh or cry. Mordake repeatedly begged doctors to remove it, claiming it whispered bad things to him at night. Mordake died by suicide at the age of 23." (The Wikipedia article of Edward Mordake)
This version is a translation of the novel into English.