The REALs of a Dream: Edgar Cayce

E.L Doctorow, author of the novel Ragtime, based the role of the Little Boy on real-life “sleeping prophet,” Edgar Cayce.  He briefly alludes to the boy’s psychic powers in the novel:

"He could look at the hairbrush on the bureau and it would sometimes slide off the edge and fall to the floor. If he raised the window in his room it might shut itself at the moment he thought the room was getting cold."

In the novel and musical, the Little Boy warns Harry Houdini to “warn the duke!” implying that if Houdini, on his trip to Sarajevo, warns the Archduke Franz Ferdinand, he won’t be shot and assassination, thus preventing the start of the first World War, instead of triggering it. 

There is no factual documentation but rumor has it that this incident actually happened. In real life, the psychic Edgar Cayce predicted the assassination to Houdini, and Houdini later recalled it as the one true mystical experience of his life. He was performing a trick over Times Square when the news came that the heir to the Austro Hungarian empire, Archduke Franz Ferdinand, was   assassinated.