Part II: The Modern Payment Stack
Having seen how money originated and how settlement systems work, we now zoom into the modern payment stack — from the moment you tap to the moment money settles between institutions.
Chapter 4 introduces the four-stage canonical payment flow (authorization → clearing → settlement → reconciliation) that anchors the rest of the book. Chapter 5 meets the cast — networks, issuers, acquirers — and Chapter 6 untangles the internet-era middle layer of gateways, PSPs, and orchestrators. Chapter 7 shows where Web3 enters the story, and Chapter 8 explains why the same payment looks completely different depending on where in the world you're standing.