This book explores how decentralized finance (DeFi) can disrupt traditional centralized finance including the business areas of insurance companies, banks, money markets, and bonds. DeFi is not a company or a single product, rather it is a collection of products or services. As part of the Ethereum ecosystem, DeFi services are provided as Decentralized Applications (dApps), which require smart contracts to lock in assets for processing transactions. Changing consumer expectations, the availability of affordable technologies, and entrepreneurial drive create space for DeFi. Geopolitical crises and trust deterioration exacerbate the need. This book explains the concept of DeFi, the technological opportunities, the current reality and status quo of business transactions, and demonstrates the potential for future use and the eventual transformation of the financial industry. It further provides a comprehensive analysis of the real-world applications of DeFi, the Decentralized Ledger Technology (DLT), and digital assets, as well as their potential risks to consumers and financial institutions to bankers, managers, investors, and policymakers.