The term "muckraker" was taken from the fictional character in John Bunyan's Pilgrim's Progress, a man who was consigned to rake muck endlessly, never lifting his eyes from his drudgery. People in the United States had long been displeased with the unsafe conditions, political corruption and social injustice of the industrial age, but it was not until the late 19th century that the proliferation of cheap newspapers and magazines galvanized widespread opposition. Writers directed their criticisms against the trusts (oil, beef and tobacco), prison conditions, exploitation of natural resources, the tax system, the insurance industry, pension practices and food processing, among others. Theodore Roosevelt, however, became angry when he read a bitter indictment of the political corruption of the day. The president, clearly one of the most fervent reformers, believed that some of the writers were going too far, and cited the muckraker image in a speech on April 14, 1906, criticizing the excesses of investigative journalism.
In "Pilgrim's Progress" the Man with the Muck Rake is set forth as the example of him whose vision is fixed on carnal instead of spiritual things. Yet he also typifies the man who in this life consistently refuses to see aught that is lofty, and fixes his eyes with solemn intentness only on that which is vile and debasing. Now, it is very necessary that we should not flinch from seeing what is vile and debasing. There is filth on the floor, and it must be scraped up with the muck rake; and there are times and places where this service is the most needed of all the services that can be performed. But the man who never does anything else, who never thinks or speaks or writes, save of his feats with the muck rake, speedily becomes, not a help but one of the most potent forces for evil.The writers, many of whom had been Roosevelt's ardent supporters, harshly criticized him for apparently deserting their cause. Originally used in a pejorative sense, the term muckraker soon developed a positive connotation in the public mind. Leading writers of this genre included: