Guys, had it not been for the title I would not even be reading this. I know nothing about paper money other than how to spend it. So I don't read this section as a general rule. But I will say this - auction estimates are for the most part meaningless. They are almost always either too high or too low. Rarely does an item ever sell for the estimate provided. The majority of the time - it's not even within the estimate range. I always thought that everybody knew this ! It doesn't take a lot of research or study to know it. If you watch even 2 auctions you'll see it easy enough. I will add this - when you see estimates consistently being too high - or too low - just 1 way or the other and not both. THAT is a sign that the market is changing and close attention should be paid.