[13] The book details the newly formed FBI's investigation of the murders, and the eventual trial and conviction of cattleman William King Hale as the mastermind behind the plot.

[15] Writing for The New York Times, Dave Eggers called the book "riveting"[16] and wrote, "in these last pages, Grann takes what was already a fascinating and disciplined recording of a forgotten chapter in American history, and with the help of contemporary Osage tribe members, he illuminates a sickening conspiracy that goes far deeper than those four years of horror.

Filled with almost mythic characters from our past – stoic Texas Rangers, corrupt robber barons, private detectives, and murderous desperadoes like the Al Spencer gang – Grann's story amounts to a secret history of the American frontier.

"[18] A reviewer of Publishers Weekly stated, "New Yorker staff writer Grann (The Lost City of Z) burnishes his reputation as a brilliant storyteller in this gripping true-crime narrative, which revisits a baffling and frightening—and relatively unknown—spree of murders occurring mostly in Oklahoma during the 1920s.

"[19] David Aaronovitch in The Times wrote, "There is a kick-in-the guts half-twist at the end of the book that gives the work its moral heft and reminds the American people of the great cost of their nationhood.

[25] The book was adapted into a film directed by Martin Scorsese and starring Leonardo DiCaprio, Robert De Niro, Lily Gladstone, John Lithgow, Brendan Fraser, and Jesse Plemons on a budget of over $200 million.