As a self-taught scholar of ancient Mesoamerican calendar traditions, John Major Jenkins has investigated the authentic underpinnings of the Maya calendar period-ending in 2012 AD. His “2012 alignment theory,” first published in 1994 and greatly elaborated in his 1998 book Maya Cosmogenesis 2012, argues that the December 21, 2012 date was selected by the ancient Mesoamerican calendar makers to target a rare alignment within the precession of the equinoxes.