This paper aims to reveal the fact that Mark Twain’s posthumous work, No. 44, the Mysterious Stranger, has already shown the phenomena of simulation analyzed in Simulacra and Simulation which was written by Baudrillard in 1981 even though Twain’s novel had been written long before in 1897-1908. Baudrillard, a French social philosopher, interprets the principle of the flow of society or symbols as a simulation phenomenon, saying that humans live in the fascinating world of simulacra created by simulation. The simulation in this novel is expressed in a virtual reality in which the heroes, No. 44 and August, travels to subdue Adolf playing the role of Karl Lueger, who was Hitler’s role model. In addition, the Duplicates outdoing the real workers who work for the print house clearly show what hyperreality is. In this world of hyperreality where simulacra outpace realities, the boundary between true and false is blurred. Having observed these social phenomena, Baudrillard argues that the serial emergence of these simulacra results in disappearance, which is consistent with No. 44’s thought, ‘nothing exists, including god.’ These factors revealed in No. 44, the Mysterious Stranger reflect how modern and creative Twain’s writing is, and serve as a chance to infer they are simulacra of Baudrillard’s simulation.