There is no earthly religion in existence that that doesn’t owe its concepts and traditions to an earlier form of itself, and as each system of belief evolves over time, the oldest methods and ideas blur into obscurity. Contemporary generations hold onto what ancestors established, not always willing to trace that belief back to its absolute origin, and what is left is at times a copy of a copy, whereupon the final image is left wanting for clarity.

This was never truer than for the Israelites, whose long history of interaction with the pagans adulterated not the Word of God, but their ways of life and religious systems throughout centuries of generations. How much, then, do we now adopt of these erroneous customs?

In 1921, W. O. E. Oesterley answered this question and countless others in Immortality and the Unseen World, which scholars have since claimed is one of the most essential works for any Bible student who wishes to understand theological concepts of the Hebrews from the supernatural realm to death, immortality, angels, and demons.