2.1 The Infrastructure of DeFi2.2 Basics of Blockchains2.3 Bitcoin and Ethereum2.4 Permissioned vs Public Blockchains2.5 L1s and L2s2.6 Accounts, Keys, Wallets, and Addresses2.7 Transactions2.8 Smart Contracts2.9 Clients and Nodes2.10 Block Explorers2.11 Custody2.12 Oracles2.13 RegTech2.14 Identity2.15 Bridges2.16 DeFi Instruments2.17 Stablecoins2.18 Derivatives2.19 Chapter SummaryNotes