Knowledge for these writings is drawn from "In the Light of Truth", The Grail Message by Abd-ru-shin.

These "Related Writings" are so-described, because their authors have drawn their knowledge from the Grail Message. Herbert Vollmann, the author of "A Gate Opens", writes in the preface to his book: "This book is intended to show how the building-bricks of the Knowledge of Creation which the Work ‘In the Light of Truth’, the Grail Message of Abd-ru-shin, gives to men, can be joined together like mosaic pieces into pictures (themes) with the aim of a gladdening spiritual experience, if in being put together the picture has emerged complete." This statement appropriately describes the books in the collection "Related Writings".