The authors of Nancy Drew, Hardy Boys, Bobbsey Twins, and many other books written for children were actually written by ghost writers for Edward Stratemeyer and his daughters. Read the article here.

When I first found this out, I had to check on my favorite sleuth when I was young, Trixie Belden. I was relieved to find out that at least the 6 books were actually written by Julie Campbell but the remainder of the series was also written by ghost writers under the pseudonym Kathryn Kenny.