Initiation is one of the most valuable experiences in any person's life. Many religions have initiatory rituals such as Confirmation, Baptism, Bar Mitzvah, and so forth. Generally, initiations are one of two types: initiation into a tradition and initiation into a group. For example, a person might be Baptized into the Christian tradition, but not align themselves with any particular church group. A person could be initiated into a fraternity or sorority which makes them a member of a group, but not of any spiritual tradition.
Occult traditions are filled with initiations. Some of the more famous initiations into groups can be found in books such as Buckland's Complete Book of Witchcraft