The Jungle, written by Upton Sinclair during the progressive era in America, was intened to show the wide gap between the quality of living of the rich and the poor. It was an argument in favor of socialism, to help reduce this gap and benefit the poor. However, it's treatment of the unsanitary conditions in meat packing plants led to reforms in government regulation of food production, for which the book is better known. It made all who read it, including the American president, Theodore Roosevelt, disgusted and angry with the way business was abusing its consumers, and quickly brought about changes in the industry.