About the book (from dust jacket):
The Capellans live among us. They are unseen. For millions of years they have been harvesting a crop of their own planting: the thought forces released by humans at death. Now their source of power and life, dependent upon human mortality, is threatened by the advance of science.
If magazine-writer Martin Enders had been aware of the approaching crisis in interplanetary affairs, his assignment to do a cover story on Dr Penn might have been easier. And the saboteurs at a remote laboratory in the South-west desert unmasked more readily. And the reasons for beautiful Virginia Penn’s behaviour made clear.
About the author (from Wikipedia):
Gerald Allan “Jerry” Sohl Sr. (December 2, 1913 – November 4, 2002) was an American television scriptwriter and science fiction author who wrote for The Twilight Zone (as a ghostwriter for Charles Beaumont), Alfred Hitchcock Presents, The Outer Limits, Star Trek: The Original Series (once using the pseudonym “Nathan Butler”), and other shows. He wrote more than twenty novels as well as feature film scripts. He also wrote the nonfiction works Underhanded Chess and Underhanded Bridge in 1973.