Before 1928 everyone baked their bread or purchased entire loaves. It was up to each person to create the perfect slice when needed.
In 1912 Otto Frederick Rohwedder, from Davenport, Iowa, began work on his future invention of the Rohwedder Bread Slicer. Naysayers said individual slices would make the bread go stale quicker. After lots of tweaking, Rohwedder's final invention in 1928 not only sliced the bread, but also wrapped it in wax paper.
By 1930 Wonder Bread began to commercially produce pre-sliced loaves of bread.
As a side note..I created some note cards with these last four Iowa food images. You can find them here. Enjoy!