The Vesper, or Vesper martini, is a cocktail, invented by author Ian Fleming in the James Bond novel Casino Royale. In the novel, Bond describes it as "three measures of Gordon's, one of vodka, half a measure of Kina Lillet. Shake it very well until it's ice-cold, then add a large thin slice of lemon peel.".
Kina Lillet is no longer manufactured, making this recipe difficult to reproduce. Some sources suggest using Lillet Blanc, but this aperitif has a very different character, since Kina Lillet was based on quinine rather than the herbal flavors found in Lillet Blanc. Nick Fisher suggests Cocchi Americano or Kina L'Aéro d'Or. Other cocktail experts also note that shaking a martini is usually discouraged, as it leaves shards of ice floating in the drink, and that stirring is the preferred method.
The Vesper Martini is on the list of International Bartender Association official cocktails, in the "Contemporary Classics" category.