Close your eyes and imagine the last moments of a massive star, large as the Solar System. As the mass of its core approaches a fatidic value, the enormous fabric collapses. The star plasma streams like a monstrous wave inward towards the center of the star. In a fraction of a second the core of the star becomes as dense as an atomic nucleus. And then a mighty outward shock wave forms, disrupting the whole structure, the star becoming almost as bright as the whole galaxy. This explosion is a supernova!Chinese observers studied with care these events since ancient times; the observation of these explosions by Tycho Brahe and Kepler was crucial for the adoption of the Copernican system. Do you know that each drop of your blood contains iron atoms produced in these cosmic cataclysms? We are literally star dust, disseminated in the galactic medium by supernovae.This book guides the reader in the discovery of these rare events, the most spectacular that the Universe can offer. Present models reproduce the explosion only with difficulty, as if some details were wrong, or a whole aspect of physics was missing from the equations. Different aspects of these events are illustrated, as well as their historical and scientific importance and their crucial role in the evolution of the galaxy and the living organisms.