The book's title is a reference to a threat spoken by the Golden State Killer during his 1976 attack upon his tenth victim, then-15-year-old Kris Pedretti, to whom he said, "You'll be silent forever, and I'll be gone in the dark.

"[1][2] After becoming interested in the crimes of what was then known as the "East Area Rapist" (among other names) McNamara wrote a 2013 Los Angeles magazine article about the serial killer, and ultimately signed a book deal with HarperCollins to write about the case.

Jensen later explained that, while McNamara had completed numerous chapters for the book, they were not in any particular order in her computer files; consequently, he, Haynes, and Oswalt mainly focused on sequencing her material and filling in gaps from her voluminous notes and copies of police documents.

[8] The book's title recalls a threat that the killer, Joseph James DeAngelo made during his December 18, 1976 attack upon his tenth victim, then-15-year-old Kris Pedretti, whom he raped three times in her home over the course of over two hours as her parents attended a Christmas party.

[15] The sheriff credited McNamara's dedication to the Golden State Killer case for raising publicity, but added that her work did not directly generate any critical tips or information that led to DeAngelo's arrest.

"[18] Jensen appeared on the My Favorite Murder episode "Golden State Serial Killer Caught", on April 26, 2018, immediately after the arrest was made, and discussed the case and his work on the book following McNamara's death.