This document discusses the balance of payments (BOP), which measures all international economic transactions between a country and foreign residents over a year. It summarizes key aspects of the BOP, including that it is a flow statement rather than a balance sheet and that it has four main accounts: the current account, capital/financial account, official reserves account, and net errors/omissions account. It also discusses how the BOP interacts with important macroeconomic variables like GDP and exchange rates.