This chapter provides an introduction into the intricate power dynamics surrounding nuclear weapons, exploring their role in shaping global politics. It outlines four central and interlinked themes: nuclear armament, proliferation, nonproliferation, and disarmament, explaining the strategic, technical, and political factors driving these processes. The chapter traces the evolution of nuclear weapons as instruments and symbols of power from their development during World War II, through the Cold War arms race, to present-day challenges. Special attention is given to the nonproliferation regime with the Nonproliferation Treaty (NPT) at its core, as well as the ongoing geopolitical tensions around nuclear deterrence and the humanitarian impacts of nuclear weapons. The chapter also addresses the complex dynamics of nuclear disarmament, highlighting the technical, economic, and political obstacles to achieving a world without nuclear weapons.