Terrence Poppa has a background in journalism, private investigations, and Islamic studies. As a journalist, he wrote a biography of a Mexican drug trafficker: Drug Lord, the Life and Death of a Mexican Kingpin, now in its third edition. Netflix's Narcos producers purchased the dramatic rights in 2018 and made extensive use of the book for Seasons 1 and 2 of their Narcos: Mexico series. In addition to Gray Wrath, he has written two other novels, Finding Ricky, a psychological thriller, and Cauldron of Wrath, a terror thriller.