If there's any one key ingredient that is critical to cooking Thai food, it is fish sauce. This is a must-buy ingredient. It smells terrible, but makes make Thai food taste great.

Fish sauce is made from small fish and salt fermented for a long time. The juice is extracted and boiled. Good fish sauce should be clear and brownish in color.

Fish sauce is not new, it was very popular in around the Medeterranian in Roman times. I once heard a report that the fishermen of Galilee were catching fish to be made into fish sauce.

In Thailand, Tipparos was the first brand that made it to most people's kitchen - when people stopped making it themselves and is still very popular. There are now a number of other great brands available available. Since Tipparos was the first, you sometimes see a other brand which try to copy their original bottle's shape and mimic them with names like "Taperos" or "Tips".