Harold Camping's prediction that the world will end Friday, Oct. 21, 2011, is not his first such prediction. In 1992, the evangelist published a book called 1994?, which proclaimed that sometime in mid-September 1994, Christ would return and the world would end. Camping based his calculations on numbers and dates found in the Bible and, at the time, said he was "99.9% certain" that his math was correct. But the world did not end in 1994. Nor did it end on March 31, 1995 — another date Camping provided when September 1994 passed without incident. Or earlier this year on May 21, when Camping spurred a nationwide marketing campaign to warn people that the world was ending. "I'm like the boy who cried wolf again and again, and the wolf didn't come," Camping told the San Francisco Chronicle in 1995. "This doesn't bother me in the slightest."