The Internal Revenue Service (IRS) is the United States federal government's tax collection agency responsible for administering and enforcing the Internal Revenue Code, the primary body of federal tax law. Established originally as the Office of Commissioner of Internal Revenue in 1862 to fund the Civil War, it evolved into the Bureau of Internal Revenue in 1913 following the ratification of the Sixteenth Amendment, which authorized income tax. In 1953, it was renamed the IRS and has since undergone significant reforms[2][5]. The IRS's core functions include **tax collection**, **enforcement of tax laws**, and **taxpayer assistance**. It collects trillions in revenue annually, processing over 271 million tax returns in the fiscal year 2023 alone and conducting hundreds of thousands of audits that resulted in billions of dollars in additional tax assessments[3]. The agency enforces compliance by investigating tax fraud and imposing penalties, while also providing services to help taxpayers understand and meet their tax obligations[1][3]. Organizationally, the IRS operates under the Department of the Treasury, led by a Commissioner appointed for a five-year term. It is structured around two main components: the Deputy Commissioner for Services and Enforcement, and the Deputy Commissioner for Operations Support, ensuring efficient tax administration and support functions[6][7]. The statutory authority for the IRS comes from the Internal Revenue Code and the Treasury Secretary's delegated powers[3][4]. Notably, the IRS has adapted to technological and legislative changes, including administering benefits related to the Affordable Care Act and implementing strategic plans like those under the Inflation Reduction Act to modernize its services and improve taxpayer experience[3][5]. The agency also emphasizes taxpayer rights and transparency, guided by the Taxpayer Bill of Rights. In summary, the IRS plays a vital role in funding the U.S. government through tax collection, enforcing compliance fairly, and evolving with technological and legal landscapes to meet modern demands. Its history, scope, and ongoing reforms make it a critical institution