This book compiles the proceedings of 6th International Congress on Blockchain and Applications 2024 (BLOCKCHAIN'24), held in Salamanca, Spain, in June 2024. The book includes 31 full papers presented in the main track that were selected among 51 submissions, highlighting theoretical advances and practical implementation of blockchain and distributed ledger technologies (DLTs). In addition, it contains 9 papers from the associated workshops and doctoral consortium that cover topics such as cybersecurity, legal aspects, and climate action. Blockchain and DLTs have revolutionized the scientific community by enabling breakthroughs in secure, decentralized data management, fostering transparency, and collaboration. Researchers are boosting innovation in areas like smart contracts, consensus algorithms, and governance models. In combination with cutting-edge technologies such as AI, metaverse, or quantum computing, blockchain and DLTs are shaping the future of digital trust and innovation.