Muckrakers

Ida Tarbell wrote a series of magazine articles detailing the business practices of Standard Oil, which appeared in McClure's and later were published in book form as The History of the Standard Oil Company (1904).

Lincoln Steffens, an investigator of corruption in state and municipal governments, published Shame of the Cities in 1904.

Upton Sinclair's The Jungle (1906) was largely responsible for federal legislation regulating food and drug practices.