God, that's such an amateur question to ask...that can easily be searched or looked up in less than a minute. Watch this four hour documentary ten times, The Ascent of Money: A Financial History of the World. Niall Ferguson, 2009 if you're able to do that, you're an ET...or prepared, to be an ET. Young and/or inexperienced traders are like the Karate Kid...while the more wiser and successful one's are Mr. Miyagi