As the first blockchain platform to introduce the concept of smart contracts, Ethereum serves as the gateway to a worldwide, decentralized computing paradigm. With this practical guide, Carlo Parisi, Alessandro Mazza, and Niccolo Pozzolini provide everything you need to know about building smart contracts and DApps on Ethereum and other virtual-machine blockchains. You'll find comprehensive coverage of Ethereum's internal workings to help you understand not just the how but also the why of Ethereum's innovative technology. You'll dive deep into the architecture and operational mechanics of Ethereum by learning essential knowledge for building and interacting effectively with DApps and smart contracts on Ethereum and similar virtual-machine blockchains. However, Ethereum now utilizes two distinct clients: one for consensus and another for execution. Instead of a reference implementation, Ethereum relies on a reference specification, a mathematical description detailed in the Yellow Paper (see “Further Reading”), which has been consistently updated throughout Ethereum’s development. Currently, the Ethereum community is transitioning towards a reference specification written in Python for both the consensus and execution clients.