"King Coal is to the mining world what Sinclair's The Jungle is to the meat-packing industry." -Library Journal
"Better than The Jungle, progresses swiftly, with many dramatic situations and a constant flow of incidents." -New York Times
"King Coal is perhaps as fine a labor novel as could be written . . . a brilliant success." -Floyd Dell, Upton Sinclair: A Study in Social Protest
"Undoubtedly impressive, a masterly delineation." -New York Tribune
"Nothing so brilliant and thrilling for many a day." -Chicago News
"The technology in the novel moves with the muscles of men and mules. But aside from changes in technology, too much of what Sinclair writes about remains a problem in mines today." -Susan Williams, Charleston Gazette-Mail
"It is seldom that truths concerning conditions in coal mines are brought to light in so readable and popular a form as Mr. Sinclair's novel." -Hazel Wilkinson, Social Thought in American Fiction
"I wish that every word of it could be burned deep into the heart of every American." -Adolph Germer
"Sinclair's achievement was impressive . . . He saw through the lies of his era and exposed a world long hidden from view. He showed compassion for the weak and the poor, the powerless and the despised . . . He fueled anger at injustice." -Eric Schlosser
"When people ask me what has happened in my long lifetime I do not refer them to the newspaper files and to the authorities, but to [Sinclair's] novels." -George Bernard Shaw
