via:
Magic by Return of Post: How Mail Order Delivered the Occult — The Public Domain Review
What allowed occultism to blossom in the United States at the turn of the 20th century? Linotype machines, cheap pulp paper, and newly improved postal networks. Allan Johnson investigates the forgotten history and (still living) world of mail-order magic.
publicdomainreview.org ↗ A fascinating deep dive into the early 20th century mail-order occult industry — how esoteric knowledge was commodified and distributed through correspondence courses, from hypnotism to Rosicrucianism.