Besides enthusiasm for tea, Mo Siegel (and one of the other company’s co-founders John Hay) was also an avid believer in a “new-age bible” called The Urantia Book. First published in 1955, the bible is inspired by Seventh-Day Adventist movement, except that it was supposedly communicated to an unknown man possessed and put into a trance by aliens. Yes, aliens. Giller explains that it was more likely written by William Sadler, a turn of the century psychiatrist who also published three books about eugenics and had a deeply rooted racist philosophy.
Source: Sleepytime Tea and the Little Known Religion Behind It