Introduction to Financial Services: The International Foreign Exchange Market [Updated November 1, 2019] [open pdf - 448KB]
From the Overview: "The international foreign exchange market is a vast, complex assortment of globally dispersed actors and transactions that comprise millions of transactions daily, valued at trillions of dollars. On a daily basis, the value of global foreign exchange transactions eclipses the total global value of economic output and the value of all traded stocks and bonds. These markets are highly liquid as a result of extensive global communications systems and electronic trading venues that operate on a 24-hour basis. Foreign exchange markets respond rapidly to political and economic events and instantaneously transmit market signals across national borders. Governments are adopting or considering regulations to curtail some aspects of the foreign exchange derivatives market and are examining challenges posed by digital currencies."
CRS Insight, IF10112
Congressional Research Service: https://crsreports.congress.gov/