"There is a physical world, which we all accept as real, but there is also a spiritual world that interpenetrates this material world and is its cause and foundation. Between these two worlds exists a threshold that can be felt, seen clairvoyantly, traversed and passed through by anyone with a real desire to do so..... At this threshold there is a guardian whose task is to stop humans from passing across it unprepared." (from the introduction)

Based on first-hand knowledge, Are Thoresen offers insights into the meaning of the threshold to the spiritual world. He describes his own experiences in encountering this threshold and going beyond it. But there are many thresholds to the spiritual world, he says, and many ways to pass them--as there are many aspects to the "guardian of the threshold" and versions of the so-called animals at the threshold. The worlds beyond, too, have a variety of different constructions--or, as the Bible says, "In my Father's house are many mansions."
The author describes the methods and techniques for opening the spiritual sense organs required to cross the threshold, and clarifies the differences between Imagination (seeing spiritual "pictures"), Inspiration (understanding those pictures) and Intuition (living "inside" the spiritual reality). Structuring the book on his own biography, Thoresen conveys many of the lessons he has learned through decades of familiarity with the invisible dimensions. However, he warns that there is only one good reason to attempt to cross the threshold, and that is to serve God and humanity in the name of love. If we do it out of curiosity, or to enhance our personal development, it would be better not to try.