This lecture covers the basics of Byzantine Fault Tolerance (BFT) and its application in Hyperledger Fabric. It discusses the challenges of achieving consensus in distributed systems, the concept of state-machine replication, and the evolution of blockchain technology from Bitcoin to Ethereum and Hyperledger Fabric. The lecture delves into the architecture of Hyperledger Fabric, the order-execute model, and the Mir-BFT protocol for total order broadcast. It also explores the performance evaluation of Mir-BFT in WAN settings and the key requirements for Hyperledger Fabric's design. The presentation concludes with insights on preventing transaction duplication, scalability, and the future prospects of Mir-BFT as a production-ready BFT library.