The Martini  cocktail is not just a drink it's a bartending mystery. One of the oldest legends surrounding the mystery of the birth of the Martini cocktail takes us back to the late 19th century, at the Occidental Hotel in San Francisco, when a traveler on his way to Martinez (California), asked the Hotel's barman to prepare something special.
Unaware that this barman was the legendary Professor Jerry Thomas, famous for his innovative cocktails, had published in 1982 the Martinez manual for bartenders which saw him recognized as one of the leading authorities in his field. Another hypothesis would return to Italy, in Liguria, where the name of Martini is still widely diffused. In all probability, the Martini cocktail has no single inventor like in the case of many a masterpiece. The one undisputable fact is that the Martini has long been associated with important events and people, not the least of whom being John D. Rockerfeller who, from the age of 71 never renounced his Martini cocktail until his last days at 98. The modern American Style Martini a squirt of Vermouth to a shot of gin - was invented at Harry's Bar in Venice to satisfy Ernest Hemingway, one of the most famous and regular client. Today the real Martini, Cosmopolitan, Martinez, Martini American Style, cannot be considered a Martini if not served in its own diamond-shaped glass, iced or cooled before serving.

Many variations exist on the standard martini.
• A vodka martini (or vodkatini or kangaroo) is made the same way but with vodka instead of gin, and more often uses lemon rind as the garnish. This is the most common variation, and in fact is more popular than the original in most locations.
• An in-and-out martini is a very dry gin martini prepared by pouring a small measure of vermouth into a shaker, shaking it to coat the ice, and then pouring out and disposing of any remaining vermouth. The standard amount of gin is then shaken over this vermouth-tinged ice and served normally.
• A Churchill is made with dry gin, stirred, with an unopened bottle of vermouth waved above the shaker.
• An apple martini (also sour apple martini or appletini) is a vodka martini with an apple flavoring such as apple schnapps, sometimes with apple, lemon or lime juice, and is often garnished with a slice of Granny Smith apple. Some people call this an "apple cosmopolitan".
• A dirty martini has some of the brine (at least a teaspoon) from the olive jar added. (FDR was partial to a dirty martini.)
• A naked martini is made without ice, but with the ingredients and glass chilled.
• A sweet martini is made with sweet red vermouth, and may be garnished with a maraschino cherry instead of an olive.
• A sake martini substitutes a dry, clear sake for the vermouth.
• A Gibson is a standard dry martini that is garnished with cocktail onions instead of olives.
• A tequila martini substitutes tequila for gin.
• An akvavit martini substitutes akvavit for gin.
• A gin salad is made like the ordinary martini but with three olives and two cocktail onions as garnish.