HOW DID IT BEGIN? A SHORT HISTORY...
1920s. It is not generally known that in the 1920s Thomas Edison tried to invent a machine that would communicate with the dead. Thinking this was possible, he wrote: "If our personality survives, then it is strictly logical or scientific to assume that it retains memory, intellect, other faculties, and knowledge that we acquire on this Earth. Therefore … if we can evolve an instrument so delicate as to be affected by our personality as it survives in the next life, such an instrument, when made available, ought to record something."
Edison never succeeded with the invention, obviously, but it seems he did believe that it might be possible to capture disembodied voices with a machine.
1930s. In 1939, Attila von Szalay, an American photographer, experimented with a phonograph record cutter in trying to capture spirit voices. It's said that he achieved some success with this method and got even better results in later years using a wire recorder. In the late 1950s, the results of his experiments were documented in an article for the American Society for Psychical Research.
1940s. In the late 1940s, Marcello Bacci of Grosseto, Italy claimed to be able to pick up voices of the deceased on a vacuum tube radio.
1950s. In 1952, two Catholic priests, Father Ernetti and Father Gemelli, inadvertently picked up EVP while recording Gregorian chants on a magnetophone. When the wire on the machine kept breaking, Father Gemelli looked to heavens and asked his dead father for help. To the shock of both men, his father's voice was heard on the recording saying, "Of course I shall help you. I'm always with you." Further experiments confirmed the phenomenon.
In 1959, Friedrich Juergenson, a Swedish film producer, was recording bird songs. On playback, he could discern his mother's voice saying in German, "Friedrich, you are being watched. Friedel, my little Friedel, can you hear me?" His subsequent recording of hundreds of such voices would earn him the title "the Father of EVP." He wrote two books on the subject: Voices from the Universe and Radio Contact with the Dead.
1960s. Juergenson's work came to the attention of a Latvian psychologist named Dr. Konstantin Raudive. At first skeptical, Raudive began his own experiments in 1967. He too recorded the voice of his deceased mother saying, "Kostulit, this is your mother." Kostulit was the boyhood name she always called him. He recorded thousands of EVP voices.
1970s and 1980s. Spiritual researchers George and Jeanette Meek joined forces with psychic William O'Neil and recorded hundreds of hours of EVP recordings using radio oscillators. They allegedly were able to capture conversations with the spirit of Dr. George Jeffries Mueller, a dead university professor and NASA scientist.
1990s to present. EVP continues to be experimented with by a number of individuals, organizations and ghost research societies.

