Quasars, short for "quasi-stellar radio sources," are extremely luminous and energetic objects found in the distant universe. They are powered by supermassive black holes at the centers of galaxies, which accrete large amounts of matter and emit immense amounts of radiation. Quasars are among the most powerful sources of electromagnetic radiation in the universe, emitting light across the entire electromagnetic spectrum, from radio waves to gamma rays. Studying quasars can provide insights into the formation and evolution of galaxies, the physics of black holes, and the history of the universe itself.