Key lime pie is probably derived from the "Magic Lemon Cream Pie" published in a promotional brochure by Borden, a producer of condensed milk, in 1931. The recipe is attributed to Borden's fictional spokesperson, Jane Ellison, and includes condensed milk, lemon juice and rind, and egg yolks. It is covered with meringue, baked, and served cold. According to the pastry chef Stella Parks, users of the recipe altered it with local ingredients; she describes it as "a stunning reminder of how deeply America's traditions are shaped by advertising".

A "Tropical Lime Chiffon Pie", using condensed milk and egg yolks, is documented in a 1933 Miami newspaper article. An "icebox lime pie", was mentioned as a specialty of the Florida Keys in 1935.and a recipe under the name "Key Lime Pie" was published in 1940.No earlier solid sources are known, despite appeals to the public. A 1927 Key West Women's Club cookbook does not mention the recipe. A 1926 restaurant menu includes "lime pie", but it is unclear what it was. Various accounts claim that it was known earlier, but none were recorded before 1933. A widely-reported story claims that William Curry's cook Aunt Sally invented it in the late 19th century. But there is no evidence for this, and the oldest version of this story dates to only 1895, in promotional materials for a Bed and Breakfast in Curry's former house.

It was in the 1950s that Key lime pie was promoted as Florida's "most famous treat" and in 1987 as "the greatest of all regional American desserts."
Without quoting directly from the text give me a summary of the history of the Key Lime Pie.
Key lime pie is an American dessert pie. It is made of lime juice, egg yolks, and sweetened condensed milk. It is best served with meringue topping and is typically cooked in a graham cracker crust.

The dish is named after the small Key limes which which have yellow juice complementing the filling which is typically yellow because of the egg yolks used.

The filling is made by simply mixing the ingredients without cooking the proteins of the egg yolks and condensed milk and the acidic lime juice curdle, thickening the mixture without baking.