Byzantine Fault Tolerance is crucial for maintaining consensus in decentralized networks, particularly those using blockchain technology. In a system with BFT, nodes are able to reach an agreement on the state of the system despite the existence of faulty nodes that may send conflicting information. This is named after the Byzantine Generals' Problem, a thought experiment that illustrates the challenges of achieving consensus in such distributed systems. BFT mechanisms are implemented to ensure that the correct nodes can outvote or ignore the faulty nodes, maintaining the integrity and availability of the network.