Introduction
For most of human history, people exchanged goods and services directly (barter) or used commodities (like shells, livestock or salt) as money. Over millennia this evolved into metal coins and paper notes, and today most money is digital. Yet each step in this evolution brought new conveniences — and new problems. This module explores how money developed from barter to bytes, the flaws and crises of traditional money, and why these problems motivated a new kind of currency.