The Negroni's origins lie in another drink called the Americano: a pleasant aperitivo, bubbly and low-proof, made of Campari and vermouth topped up with soda water. It's the sort of thing Italians like to drink before dinner to wake up the appetite. There's nothing wrong with the Americano, but a single inspired substitution— gin in place of the soda water — turns it into a very serious cocktail indeed. Not necessarily because it's stronger, though it certainly is that, but because the gin's botanical complexity works so well with the intensely bittersweet Campari and the herbal aromatics of the vermouth.