My ggrandfather (great grandfather) Jake the Tailor - NOT! A cardinal rule of historical research is to go first to the primary source; see it for yourself if you can. One of the most useful sources for researching families in the United States is the U.S. Census.
They have been released and transcribed over the years to 1940, and can be viewed at FamilySearch.org, and are an incredibly useful tool for researching family. When I was searching for my great-grandfather Jacob, who was a county sheriff in Minnesota, imagine my surprise when his occupation was “tailor” in the 1880 census. So I went to the image of that page of the census. It seemed clear to me that it read “jailor”, not tailor. Lesson learned: it’s great to have documents transcribed and indexed, but nothing beats looking at the original. Of course, there’s always the issue of undecipherable handwriting – but more about that in another post.