Here is a one sided advertising piece for Natural Law in the Spiritual World. This little flyer is 6″ x 3.5″.

There is no evidence that this title was published as a non series book.

Based on the address and general look of the flyer, it was published in the 1890-1894 era.

In this time frame Natural Law in the Spiritual World appeared in three series:

Altemus Library
Fairmount Series
Laurel Series

The books in these series did not cost 50 cents and were not “maroon and white” as per the flyer.

Thus, a mystery.