The Gold Standard is a monetary system in which the standard economic unit of account is a fixed weight of gold.
You can employ this system in a various number of ways. You can use gold coins as money directly, for instance, one gold coin has 1oz of gold in it and we set a fixed exchange rate so that $1000 equals one ounce of gold. That exchange rate will stay constant no matter what. Now because carrying gold coins is not the most efficient method of currency, we can have a system whereby money is only created when there is the proper gold in the vault to back it up. If the treasury holds 1oz of gold, the treasury would be allowed to print $1000 of paper money. The holder of this gold backed paper money has the right at any time to go to the treasury and exchange the paper back into gold. For much of our history this was the system we had. In fact, our Constitution says that only gold and silver shall be used for money. Our gold standard history and its abandonment is also the history of our economic degeneration.
Now there are those who will argue that this system had its short comings. If by shortcomings they mean that the government could not run huge deficits and go to war on a regular basis, then yes, it did have big short comings. This country became the most prosperous nation in the world using this gold standard.
There are alternatives to exclusively using gold. Silver or other commodities can be used to back the creation of money, which may make it even a better system but the most important thing to understand is that your money would have real value; that is, so long as people think gold is worth something. We have for thousands of years and obviously we still do today, so I would say there is a very good shot we will tomorrow.
The gold standard also limits the money supply and prevents credit bubbles and inflation, which are the exact two things that have helped wipe out our middle class. Another thing it promotes is saving. One is more inclined to save when the value of their money remains as strong as the day they earned it. If not stronger. The only type of money that is honest, just and fair is hard money; money with something real and tangible backing it. Everything else is just counterfeit.