We mention this tip in the Mac OS 8.1 Special Report, but we still continue to get email asking about it. So it seems worth repeating:
In Mac OS 8.1, if you have a window in the Finder set to display "as List," you may occasionally find that the files in the window are listed in reverse alphabetical order (z to a). This is not a bug. It is a new option in 8.1. There is a "pyramid" icon in the upper right corner of the window, at the end of the row giving the column heading names. Click this icon and the list of names will resort in their normal order. Most likely, if the reverse sort was unintended on your part, you probably unintentionally clicked the pyramid icon on some previous occasion.