Do you have a nickname that you use instead of your given name? You may even sign documents using your nickname, rather than your given name.
Well, our ancestors did the same thing. Let's say Dorothy Smith went as Dottie Smith back in 1885. She signed official papers that way and gave her name in the census as Dottie.
One day, Dottie's great-great-granddaughter is searching for her in the census and can't find Dottie, though lots of Dorothy's seem to fit the other data she has.
And, while Ancestry.com does search for nicknames, they don't catch all of them.
If you've ever had this experience, Nicknames Past and Present will help you. It's a simple book that lists names and their nicknames. I found a lot of nicknames that I would never have traced back to the given name listed.
The book is available on Amazon for $9.95: Nicknames Past and Present, by Christine Rose