The history of the Gin Fizz goes back all the way to the very first cocktail book ever written: "How to Mix Drinks" by Jerry Thomas, 1862. The original recipe called for "hollands," or as we now know it, genever gin. But the modern day Gin Fizz is most often made with the more common London Dry Gin. The Gin Fizz is often confused with another famous gin drink, the Tom Collins. The two drinks are remarkably similar (and good!) and the only discernable difference is that the Gin Fizz is served without ice whereas the Tom Collins is served with.