From Ian Flemming's classic "Casino Royale" novel, in which James Bond, while playing poker, orders the drink: "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. Got it?" Kina Lillet is no longer made, so Cocchi Americano (or sometimes Lillet Blanc) is substituted. We also double the ratios of vodka and apertif wine to balance it out a bit more.
A very drinkable stirred cocktail. A bit sweeter than a Martini with the apertif wine and therefore (in my humble opinion) a more balanced drink. Very nice for a late night game of cards.