The Human Aura

Advanced Thought Publishing Company was a prominent Chicago-based publisher specializing in "New Thought," occultism, and self-help literature during the early 20th century.

A dark, rectangular, and grainy ink smudge or stamp is located near the bottom of the page, appearing heavily pixelated and illegible.
This mark is likely a library ownership stamp or a distributor's mark that has become obscured through repeated use or the digital scanning process.