Fill a mixing glass with ice cubes.
Add the gin and dry vermouth.
Stir continuously for approximately 30 seconds until well chilled and properly diluted.
Strain into a chilled martini cocktail glass.
Express the oil from a lemon peel over the surface of the drink and use as garnish, or garnish with a green olive if preferred.
The ratio of gin to vermouth is the defining variable of this cocktail - the IBA specifies 6:1, but many bartenders adjust to taste. Always stir, never shake: shaking over-dilutes and clouds the drink, robbing it of its signature clarity and silky texture.
My Bar Shelf reads your shelf and shows you every cocktail you can make from what you already own, including Dry Martini.