Here is a video with Mr. Detlev Schlichter discussing Gold vs Fiat money. In his book, Paper Money collapse, he reviews the problems with Paper Money, specifically on how it relates to the Central Government's ability to spend and expand credit. For an example of this currency depreciation in the current news, see this article, "Dollar near lowest month after Bernanke Speech"
The Fed works with the Federal Government to print more money and keep interest rates low to spur on economic growth. This causes and creates asset bubbles, which eventually correct as Mr. Schlichter explains in this video. The lack of savings, and the egregious use of borrowing and spending leads to disastrous results.