This first course of the Blockchain series provides a broad overview of the essential concepts of blockchain technology – by initially exploring the Bitcoin protocol followed by the Ethereum protocol – to lay the foundation necessary for developing applications and programming. Participants learn about the decentralized peer-to-peer network, an immutable distributed ledger and the trust model that defines a blockchain. Content includes the hashing and cryptography foundations indispensable to blockchain programming. Along with the other courses of the Blockchain specialization, it provides the foundation needed for developers who seek to design and develop smart contracts and decentralized applications on the blockchain.