In 1926, Walter Russel wrote the following as the first paragraph in the prelude of "the Universal One":
The supreme service which man can render to evolving man is to answer for him, dynamically, the great heretofore unanswerable question concerning the One universal force which man calls God, or Mind, or by other names.
I encountered the diagrams from this book earlier as well, but like it is said, the insight will only come once you are ready for it. Before that time it will simply not register. But now, about a century after he wrote this, I am seriously diving into it, and discovering its coherence with my own insights over the six decades my life now spans...