Byzantine Fault Tolerance (BFT) is a concept in computer science that ensures a system can continue to function correctly even when some of its components fail or act maliciously. It is named after the "Byzantine Generals' Problem," which illustrates the challenges of achieving consensus among distributed parties when some may not cooperate. BFT is crucial in distributed systems, such as blockchain networks, where multiple nodes must agree on the state of the system. By using algorithms that can tolerate a certain number of faulty nodes, BFT helps maintain reliability and security, ensuring that the overall system remains operational despite potential failures.