Concerning Paul Twitchell's book, The Key to Eckankar and Rebazar Tarzs.
The Key to Eckankar is about 43 pages of text. Similarities (near or exact) between text for The Key to Eckankar and writings of Neville Goddard appear on, or about pp. 5-6; the writings of Talbot Mundy, p. 6; Neville Goddard pp. 6-7; Thomas Troward, pp. 8-9; Talbot Mundy, p. 14; Neville Goddard, p. 17; Joel Goldsmith, p. 19; Talbot Mundy, pp. 23-25, 27; Scientology Dynamics, p. 27; Neville Goddard, p. 28; Scientology Axioms, p. 37; Joel Goldsmith, pp. 40-42.
List of the books and links:
The Power of Awareness, Neville Goddard (1952)
http://ia600202.us.archive.org/11/items/ThePowerOfAwareness/Neville_ThePowerOfAwareness.pdf
Old Ugly Face, Talbot Mundy (1940)
http://arthursclassicnovels.com/mundy/ugfa10.html
Lectures on Mental Science, Thomas Troward (1909)
http://www.archive.org/stream/edinburghlecture00trow#page/n7/mode/2up
Scientology, Hubbard (1950s?)
http://learn.scientology.org/wis4_12.htm
Practicing the Presence, Joel S. Goldsmith (1958)
http://www.scribd.com/doc/82916572/Practicing-the-Presence-of-God-Joel-S-Goldsmith
https://groups.google.com/d/msg/alt.religion.eckankar/L3IHK0Odr3M/FogQ_Ol2DAAJ