The purpose of a blockchain ledger is to provide a secure, immutable record of transactions that multiple parties can access. Its decentralized nature ensures that no single entity controls the data, enhancing trust and transparency. Each block in the chain contains a set of transactions, cryptographically linked to the previous block, creating a chronological record. This technology is widely utilized in sectors like finance, supply chain, and healthcare, allowing for auditability and minimizing fraud. By using consensus mechanisms, blockchain ledgers facilitate a reliable method of verifying transactions without intermediaries, improving overall data integrity.