In this lecture from the Yale Quantum Institute Course on Quantum Error Correction, held at Yale University in July 2025 in partnership with North Carolina A&T, physicist Steve Girvin introduces the foundations of classical and quantum error correction. The lecture lays out why quantum information is fragile and how classical error correcting codes provide a conceptual starting point before extending the ideas into the quantum domain. As the opening session of a short course aimed at building a working understanding of error correction for quantum computing, it establishes the vocabulary and core problems that the following lectures in the series build upon, including stabilizer codes and hardware level encoding schemes.