I've always studied The Greats when I started trading, I skipped the millionaires and started studying the Billionaires. Last May (2016) I wrote an article called "Top 5 Successful Forex Billionaires" and it was precisely aimed at answering your question. I did some pretty extensive research. Give it a quick read. I'm not saying that these billionaires made "all of their money" just by trading the Foreign Exchange markets, but they certainly have made billions from it or it helped give them a great push.