The In & Out Martini is a classic Gin martini that substitutes Dry Vermouth for the sweet vermouth typically used in the drink. This gives the In & Out Martini a drier, more astringent flavor than a traditional gin martini. The history of the In & Out Martini is unclear, but it is thought to have originated in the early twentieth century. It is named for its simplicity: it only contains two ingredients, gin and dry vermouth. The In & Out Martini is a popular choice for those who prefer a drier martini. Cheers!