Accardi's Law is a principle in the field of quantum mechanics that states that the probabilities of certain outcomes in a quantum system can be derived from the properties of the system's underlying algebra. It emphasizes the importance of the mathematical structure of quantum theory in predicting physical phenomena. This law is named after Francesco Accardi, an Italian mathematician and physicist, who contributed significantly to the understanding of quantum probability. Accardi's Law helps bridge the gap between abstract mathematical concepts and their practical applications in understanding quantum systems and their behaviors.