The Ceremony of Initiation
by W.L. Wilmshurst
Initiation can be viewed as a door opened through which one can pass if they so desire. Freemasonry has from its earliest days employed initiation as their tie to the Ancient Mystery Schools. It is the method of initiation that separates Masonry from other clubs and associations. In this classic work, W.L. Wilmshurst explains meanings of the first initiation Freemasons experience.
Available at Kindle
While it is geared towards Masonic initiation and uses that as an example, it helps to explain the initiation process for many institutions. It also helps those who have or are going to become Masons, understand more deeply the spiritual aspects of initiation.
~ E. Croft