Other critiques of the press had appeared, but Sinclair reached a wider audience with his personal fame and lively, provocative writing style.

[1] Among those critiqued was William Randolph Hearst, who made routine use of yellow journalism in his widespread newspaper and magazine business.

The editors and journalists of the Associated Press (AP) wire service fail to serve the public interest in the same way as employees of the individual papers.

[4] Sinclair quotes a letter from the editor of the weekly San Francisco Star, James H. Barry: You wish to know my "confidential opinion as to the honesty of the Associated Press."

Its news-gatherers, I sincerely believe, only obey orders.Among the recent events whose media coverage he discusses are the Paint Creek–Cabin Creek strike of 1912 in West Virginia, the Ludlow Massacre in Colorado in 1914, Industrial Workers of the World meetings, and the Red Scare whipped up by the newspapers.

"[7] Sinclair challenged those who charged him with inaccuracy to review his published facts and to sue him for libel if they found he had been wrong.

But because Sinclair was denied access to the mainstream media to refute those charges, they assumed the aura of truth and gave the book a reputation for inaccuracy that caused it to be almost forgotten by midcentury.

[3] Press watchdogs at the time of publication and recently find The Brass Check's analysis of the media accurate and valuable.

"[3] And "those historians who bother to mention The Brass Check dismiss it as ephemeral, explaining that the problems it depicts have been solved.