The muckrakers were a group of investigative journalists and writers in the late 19th and early 20th centuries who aimed to expose corruption, social injustices, and unethical practices in various sectors, including government, business, and society. Their work played a significant role in the Progressive Era, shedding light on issues such as labor rights, child labor, and corporate greed. Notable muckrakers included Upton Sinclair, whose novel "The Jungle" revealed the harsh conditions of the meatpacking industry, and Ida Tarbell, who investigated the monopolistic practices of Standard Oil. Their efforts contributed to significant reforms and increased public awareness of societal issues.