A book classified by the CIA for more than 50 years contains a shocking theory about how the world will end.

“The Story of Adam and Eve,” written by ex-US Air Force officer, UFO researcher, and self-proclaimed psychic Chan Thomas, was written in 1966 but was stopped from publication by order of his agency

It was “quietly” declassified in 2013, at least in part, but remained hidden in the CIA database — until now.

In the book, Thomas claims that every 6,500 years, a major catastrophe on the scale of the Biblical “Great Flood” hits the Earth.

While experts debate the exact date of that flood in the Book of Genesis, Thomas claims it happened about 6,500 years ago, and there is some archaeological and geological evidence to support this claim.

By this logic, he argues that the next disaster is near, in terms of time.

As for what the end of the world will look like, he believes the Earth’s magnetic field will suddenly, drastically shift, wreaking havoc on the entire planet.

The reason the book in question was classified remains unclear, but some have argued that the agency was concerned it would cause mass panic or that it contained information related to a secret government investigation.

Thomas in particular had tackled classified projects during his tenure at the defunct McDonnell Douglas aerospace company.

He was part of a small team of scientists assembled by the company to investigate reports of UFOs.

Although there are no official records that he worked directly for the CIA, the nondisclosure clause the agency places on its employees entails obtaining approval should they wish to publish a book or paper in the future.