Wave-Particle Duality is a fundamental concept in quantum mechanics that describes how particles, such as electrons and photons, exhibit both wave-like and particle-like properties. This duality means that under certain conditions, particles can behave like waves, displaying interference and diffraction patterns, while in other situations, they act like discrete particles, with defined positions and momenta. The concept was famously illustrated by the double-slit experiment, where light and matter create patterns that suggest they can be in multiple states at once. This phenomenon challenges our classical understanding of physics and has profound implications for the nature of reality, leading to the development of quantum theory and its applications in technology, such as quantum computing and semiconductors.