Harksaw:
After Roosevelt's executive order required everyone to turn in their gold coins to be melted, how is it that there are still so many gold coins available to collectors? Were they all either held illegally, or held overseas?
Sorry to be too lazy to provide references, and this is all from memory, but my understanding is that before gold was banned, people anticipated that the main thing the government was going to do was redefine a dollar to be some amount less than 1/20th of a troy ounce of gold. The law was written to allow a dollar to be redefined to be redeemable for as little as 1/35th of an ounce of gold. This made two things happen. The first is that a whole lot of physical gold flowed out of the United States and into Europe. I assume this is the main reason why there are double eagles still available.
The second thing that happened is more diabolical. The law banning the use of gold as money didn't entirely ban the posession of gold. If memory serves, people were allowed to keep something like $100's-worth of gold (i.e. five troy ounces), which at the time was an average month's salary (again, from memory). So most people's perception of the law was that the switch to de facto fiat currencey was going to effectively put $75 dollars into their pocket if/when they traded their 5 ounces of gold for $175. Of course we understand that those dollars were worth less than the original gold-backed $100, but it fooled enough people, or people were simply desperate enough, that allowing for this tiny personal allowance for gold bought the measure the political support it needed to pass.