Miguel Coyula is an “uncomfortable” figure, something indicated by the professional marginalization he faces in Cuba.

A foundational 1956 study of the concept, focussed on a U.F.O. doomsday cult, has been all but debunked by new research.

Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Robert Kelly is managing director of XTS ...