For more than a century the Witnesses have eagerly calculated the arrival of Judgement Day, when they believe only they and their followers will be saved. A chosen 144,000, known as the Anointed, will go to heaven, while the rest live in earthly paradise.
But in this month's Watchtower, the official journal of the church, senior figures say there will be no further speculation on a specific time for the end of the world. "Eager to see the end of this evil system, Jehovah's people have at times speculated about the time when the Great Tribulations would break out," the journal explains. "We do not need to know the exact timing of events. Rather our focus must be on being watchful, cultivating strong faith, and keeping busy in Jehovah's service."
The first date was set by Charles Russell, founder of the movement, who suggested the end would come by 1914. After Mr Russell's death in 1916, "Judge" Rutherford took over as leader, and had deeds drawn up holding his house in San Diegoin trust for Noah, Isaac, David, Gideon, and Joshua, who, he believed, would return to Earth after Armageddon.
Two more disappointments followed in 1925 and 1975, both set as dates for Armageddon, when Witnesses sold their homes and set off preaching full-time, in an attempt to save as many people as possible. The sense of anti-climax was so acute that when the end failed to come, thousands left the church.
When 1914 passed without the end of the world, the Witnesses decided instead that the year had been the one in which Jesus had returned invisibly to earth in anticipation of Judgement Day. But no solace could be offered for the subsequent failures.
We are still, as J M Keynes might have put it, all doomed in the long run. A spokesman for the Jehovah's Witnesses said that although followers were being encouraged to be less specific about the date, the final outcome would not be affected. "We still say we are living in a system that must end," he said.
"It's natural people would be anxious to know the exact date, but it doesn't adjust the time in which we live. These are the days in which we will see the establishment of God's kingdom, ending wickedness and bringing peace and harmony. Jesus said the day, the hour knows no one, and we accept that."