Adolf Hitler remains one of the most consequential and reviled figures in modern history, serving as the dictator of Germany from 1933 until his death in 1945. As the leader of the Nazi Party, he orchestrated the outbreak of the Second World War in Europe and is centrally responsible for the Holocaust, the systematic genocide of approximately six million Jews alongside millions of other victims. His reign of terror transformed Germany into a totalitarian state and left an indelible scar on the twentieth century, with historian Ian Kershaw describing him as "the embodiment of modern political evil." Hitler's legacy is one of unprecedented destruction, marking him as a singularly infamous figure whose actions continue to shape global politics and historical discourse.

Born on 20 April 1889 in Braunau am Inn, Austria-Hungary, Hitler was the fourth of six children to Alois Hitler and Klara Pölzl. His early life was marked by a strained relationship with his authoritarian father and a deep attachment to his mother, whose death in 1907 profoundly affected him. After failing to gain admission to the Academy of Fine Arts in Vienna twice, he lived a bohemian existence in the Austrian capital, subsisting on orphan's benefits and selling postcards. It was during this period that he developed the virulent antisemitism and pan-German nationalism that would define his political ideology. In 1913, he relocated to Munich, Germany, and when the First World War broke out in 1914, he volunteered for the German Army, serving as a dispatch runner on the Western Front. His wartime service earned him the Iron Cross, though he never rose above the rank of corporal, and the German defeat in 1918 left him embittered and convinced that the army had been betrayed from within.

Following the war, Hitler remained in the military as an intelligence officer and was tasked with monitoring political groups, which led him to the German Workers' Party in 1919. He joined the small nationalist organization and quickly became its most prominent orator, using his charismatic and inflammatory speeches to rail against the Treaty of Versailles, Jews, and communists. By 1921, he had assumed leadership of the party, renaming it the National Socialist German Workers' Party, or Nazi Party. His first attempt to seize power came in November 1923 with the Beer Hall Putsch in Munich, a failed coup that landed him in prison. During his incarceration, he dictated the first volume of his autobiography and political manifesto, Mein Kampf, which outlined his racist worldview and expansionist ambitions. Released after just over a year, he resolved to obtain power through legal means, rebuilding the party and exploiting the economic turmoil of the Great Depression to gain electoral support.

The Nazi Party's electoral success culminated in Hitler's appointment as Chancellor of Germany on 30 January 1933, a position he secured through political backroom dealings with conservative elites who believed they could control him. Within months, the Reichstag Fire and the subsequent Enabling Act of 1933 gave him dictatorial powers, and following President Paul von Hindenburg's death in August 1934, Hitler merged the offices of chancellor and president to become the Führer und Reichskanzler. His domestic policies were brutal and racist, systematically stripping German Jews of their rights, citizenship, and property while also persecuting political opponents, homosexuals, Roma, and the disabled. His early years in power also brought rapid economic recovery through massive public works projects and rearmament, which earned him considerable popular support among a population weary of depression and national humiliation. Internationally, he defied the Treaty of Versailles by remilitarizing the Rhineland, annexing Austria, and seizing the Sudetenland, each move met with appeasement from Britain and France.

Hitler's ultimate goal was the acquisition of Lebensraum, or living space, for the German people in Eastern Europe, a pursuit that led directly to the invasion of Poland on 1 September 1939 and the outbreak of the Second World War. His military ambitions initially met with stunning success, as German forces conquered much of Europe and invaded the Soviet Union in June 1941, followed by a declaration of war on the United States later that year. However, the tide turned after 1941, and as the war ground to a catastrophic defeat, Hitler's grip on reality became increasingly delusional. He withdrew to the Führerbunker in Berlin, where on 29 April 1945 he married his longtime companion, Eva Braun, and the following day, with Soviet troops closing in, the couple committed suicide. The war he ignited would ultimately claim the lives of tens of millions of soldiers and civilians, with an estimated 19.3 million deliberate killings of civilians and prisoners of war attributed to the Nazi regime, making his legacy one of the darkest chapters in human history.