From PKD’s FBI File:
Federal Bureau of Investigation
I am a well-known author of science fiction novels, one of which dealt with Nazi Germany (called MAN IN THE HIGH CASTLE, it described an “alternate world” in which the Germans and Japanese won World War Two and jointly occupied the United States). This novel, published in 1962 by Putnam & Co., won the Hugo Award for Best Novel of the Year and hence was widely read both here and abroad; for example, a Japanese edition printed in Tokio (sic) ran into several editions. I bring this to your attention because several months ago I was approached by an individual who I have reason to believe belonged to a covert organization involving politics, illegal weapons, etc., who put great pressure on me to place coded information in future novels “to be read by the right people here and there,” as he phrased it. I refused to do this.
The reason why I am contacting you about this now is that it now appears that other science fiction writers may have been so approached by other members of this obviously anti-American organization and may have yielded to the threats and deceitful statements such as were used on me. Therefore I would like to give you any and all information and help I can regarding this, and I ask that your nearest office contact me as soon as possible. I stress the urgency of this because within the last three days I have come across a well-distributed science fiction novel which contains in essence the vital material which this individual confronted me with as the basis for encoding. That novel is CAMP CONCENTRATION by Thomas Disch, which was published by Doubleday & Co.
Philip K. Dick
3028 Quartz Lane Apt. #2
P.S. I would like to add: what alarms me most is that this covert organization which approached me may be Neo-Nazi, although it did not identify itself as being such. My novels are extremely anti-Nazi. I heard only one code identification by this individual: Solarcon-6.
Nice list by wikipedia although I am not convinced that the Fed Ex package in Cast Away is a MacGuffin.