Foreign Exchange describes the purchase of a particular currency from an individual or institution and the simultaneous sell of another currency at the equivalent value or current exchange rate. Essentially, the process of exchanging one currency for another is a simple trade based on the current rates of the two currencies involved.

At the core level of the world’s need for money exchange is the international traveler. When traveling from the US to England, for example, you will of course need the local currency to pay for transportation, food, and so on. Upon arrival at the airport you will surrender (sell) your US Dollars in order to receive (buy) the equivalent in British Pounds. In this example, you sold the USD and bought the GBP, conversely the foreign exchange counter bought the USD and sold the GBP. The prices at which you buy and sell currencies at are known as exchange rates. This rate or price fluctuates based on demand, political, and economic events surrounding each country’s currency.

The example above illustrates foreign currency trading in basic terms as it relates to world travelers. However, the market is also utilized globally by each country's central bank (i.e., America's Federal Reserve), investment and commercial banks, fund management firms (mutual funds and hedge funds), major corporations, and individual investors or speculators. Depending on the timing of such transactions, purchasing a currency with the intent of later selling it at a better exchange rate (and vice versa) can potentially yield profits for investors, of course there is a strong potential for loss trading currencies as well.

Utilization by so many parties is why the Foreign Exchange market is the world's largest financial market, with a daily dollar volume exceeding $1.9 trillion ($1,900,000,000,000). This mind boggling volume is probably what led you to research the topic.

Now let's put the market's trading volume in perspective. In 2003 the reported trading volume for the NYSE (New York Stock Exchange) was a mere $9.6 trillion; the previous year was just above that at $10.2 trillion. These seem like respectable figures, but in comparison to the Foreign Exchange Market, which is commonly trading $1.9 trillion in a single day, these numbers pale in comparison. This is probably why so many fund managers and Fortune 500 companies invest heavily in this highly liquid market. The high volume of this market makes it one of the riskiest markets to trade in.

It is important to note that retail traders, such as yourself, will most likely be accessing the off-exchange foreign currency market (or Forex market) via an FCM (Futures Commissions Merchant) or broker. You will not be trading in the actual Interbank market itself. Your access to the total market will be determined by your chosen broker’s limitations. FCMs or brokers act as a bridge between you and their liquidity partner (sometimes larger global banks) that you would otherwise not have sufficient capital to do business with. The large majority of off-exchange retail foreign currency brokers act as market makers, meaning that by keeping many trades in house they create their own liquidity. Some retail brokers clear trades directly through to the larger banks that provide their liquidity. If you are new to the Forex market it would wise to research and understand your broker’s particular business model and method of clearing trades.

Unlike other financial markets, the Forex market operates 24 hours a day, 5.5 days a week (6:00 PM EST on Sunday until 4:00 PM EST on Friday). Through an electronic network of banks, corporations and individual traders exchange currencies, though as the market is primarily used as a means for speculative investing, actual physical delivery of currencies is almost never intended. Forex trading begins every day in Sydney, moves to Tokyo, followed by Europe and finally the Americas.

Many centuries ago, the value of goods were expressed in terms of other goods. This sort of economics was based on the barter system between individuals. The obvious limitations of such a system encouraged establishing more generally accepted mediums of exchange. It was important that a common base of value could be established. In some economies, items such as teeth, feathers even stones served this purpose, but soon various metals, in particular gold and silver, established themselves as an accepted means of payment as well as a reliable storage of value.

Coins were initially minted from the preferred metal and in stable political regimes, the introduction of a paper form of governmental I.O.U. during the Middle Ages also gained acceptance. This type of I.O.U. was introduced more successfully through force than through persuasion and is now the basis of today’s modern currencies.

Before the first World war, most Central banks supported their currencies with convertibility to gold. Paper money could always be exchanged for gold. However, for this type of gold exchange, there was not necessarily a Centrals bank need for full coverage of the government's currency reserves. This did not occur very often, however when a group mindset fostered this disastrous notion of converting back to gold in mass, panic resulted in so-called "Run on banks " The combination of a greater supply of paper money without the gold to cover led to devastating inflation and resulting political instability.

In order to protect local national interests, increased foreign exchange controls were introduced to prevent market forces from punishing monetary irresponsibility.

Near the end of WWII, The Bretton Woods agreement was reached on the initiative of the USA in July 1944. The conference held in Bretton Woods, New Hampshire rejected John Maynard Keynes suggestion for a new world reserve currency in favor of a system built on the US Dollar. International institutions such as the IMF, The World Bank and GATT were created in the same period as the emerging victors of WWII searched for a way to avoid the destabilizing monetary crises leading to the war. The Bretton Woods agreement resulted in a system of fixed exchange rates that reinstated The Gold Standard partly, fixing the USD at $35.00 per ounce of Gold and fixing the other main currencies to the dollar, initially intended to be on a permanent basis.

The Bretton Woods system came under increasing pressure as national economies moved in different directions during the 1960’s. A number of realignments held the system alive for a long time but eventually Bretton Woods collapsed in the early 1970’s following president Nixon's suspension of the gold convertibility in August 1971. The dollar was not any longer suited as the sole international currency at a time when it was under severe pressure from increasing US budget and trade deficits.

The last few decades have seen foreign exchange trading develop into the worlds largest global market. Restrictions on capital flows have been removed in most countries, leaving the market forces free to adjust foreign exchange rates according to their perceived values.

In Europe, the idea of fixed exchange rates had by no means died. The European Economic Community introduced a new system of fixed exchange rates in 1979, the European Monetary System. This attempt to fix exchange rates met with near extinction in 1992-93, when built-up economic pressures forced devaluations of a number of weak European currencies. The quest continued in Europe for currency stability with the 1991 signing of The Maastricht treaty. This was to not only fix exchange rates but also actually replace many of them with the Euro in 2002.

Today, Europe has embraced the Euro in 12 participating countries. The physical introduction of the Euro on January 1, 2002 saw the old countries currencies made obsolete on July 1, 2002.

In Asia, the lack of sustainability of fixed foreign exchange rates has gained new relevance with the events in South East Asia in the latter part of 1997, where currency after currency was devalued against the US dollar, leaving other fixed exchange rates in particular in South America also looking very vulnerable.

While commercial companies have had to face a much more volatile currency environment in recent years, investors and financial institutions have discovered a new playground. The size of the FOREX market now dwarfs any other investment market.

It is estimated that more than USD 1,200 Billion are traded every day, that is the same amount as almost 40 times the daily USD volume on the American NASDAQ market.