Memristors are a fourth fundamental circuit element along with the resistor, capacitor, and inductor. A memristor is a two-terminal device that relates magnetic flux and charge, allowing it to remember what has passed through the circuit. Its resistance varies as a function of flux and charge. Memristors could allow for quicker device boot up since information is not lost when turned off, use less energy than current memory devices, and may revolutionize computing and artificial intelligence. Major companies are researching memristors and their potential applications in memory, computing, and more.