The Sherman Antitrust Act is a landmark U.S. law passed in 1890 aimed at promoting fair competition and preventing monopolies. It makes it illegal for companies to engage in practices that restrain trade or commerce, such as price-fixing or forming cartels. This act was a response to growing concerns about the power of large corporations, known as trusts, which could manipulate markets and harm consumers. The act is named after Senator John Sherman, who believed that competition was essential for a healthy economy. Over the years, the Sherman Antitrust Act has been used to break up monopolies and protect consumer rights, shaping the landscape of American business practices.