http://en.wikipedia.org/wiki/George_Adamski

First: When I saw his second book on a store self, I thought: Visitors from outer space; "interesting" could that be true.

I picked up the book and read parts of the beginning, I realized that, weather truth or fiction, very "deep thoughts" had been inserted into the writing.

In 1949 Adamski wrote a science fiction book which had a space travel theme. Called Pioneers of Space: A Trip to the Moon, Mars and Venus and published by Leonard-Freefield Co of Los Angeles, the book has been claimed to have been intended mainly for his students and to test public reaction to the idea of life on other planets. Adamski took some of the fictional material from that book and presented it as fact within "Flying Saucers Have Landed".

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Adamski later claimed to have met other people from other planets (mostly from Venus but also from Mars and Saturn) and said he was taken on flights by them, including one around to the back side of the Moon where he saw cities, UFO landing strips, and mountains covered with trees and snow. Observations by Project Apollo and unmanned lunar missions such as Lunar Orbiter and Clementine have since refuted these claims (Klass 1983:161).

In 1957, James Moseley and Gray Barker wrote a fake letter to Adamski on stolen letterhead from the US State Department. This letter said that some people in the State Department knew that Adamski's claims to be true. The letter was signed by "R. E. Straith" of the non-existent Cultural Exchange Committee of the State Department. Adamski used this letter to bolster his claims. Some UFO true believers continue to believe that the letter is genuine, despite Moseley's confession of the hoax in January 1985. The Straith letter was the most successful hoaxed UFO document until the Majestic 12 documents were produced in 1987 (Moseley and Pflock 2002:124-27, 331-32), (Peebles 1994:133-34).

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Adamski said that photographs taken by the Soviet lunar probe Luna 3 in 1959 were fakes, a claim which proved to be unfounded. After he announced he was going to Saturn for a conference, many of his supporters became disaffected and his reputation rapidly declined. He died at age 74 of a heart attack in Maryland.