In my mid-twenties, however, when I first started traveling in Europe, I discovered cocktails. And it quickly dawned on me, as I sipped these attractive concoctions, that my favorite ones—martinis and negronis, above all—were based on gin.

Gin, I think it is safe to say, is the veritable king of cocktails. It seems born to mix, born to swirl and eddy in a glass in graceful counterpoint to other elements, alcoholic and otherwise. Its marriage with dry vermouth in the classic martini is particularly successful, of course—though now that I've investigated gin's origins a bit, I can't help wondering if whoever created that signal cocktail wasn't trying, at least subconsciously, to give back to gin some of the complexity and faint sweetness it possessed in its first incarnation.

Gin—or at least the precursor of gin as we now know it—was invented in 1650, when a Prussian-born physician and anatomist at the University of Leiden in Holland, one Franciscus Sylvius (ne Franz de le Boe), experimentally infused distilled grain spirits with juniper berries for medicinal purposes. The resulting potion, which Sylvius recommended as a cure for cold feet and insomnia, turned out to be good enough to drink.

The Dutch word for juniper, and by extension for the alcohol infused with it, is jenever, or genever—of which our word gin is a corruption. Jenever remains a popular tipple in the Netherlands. The cheap stuff is head-crushing firewater; but at its best, it can be a remarkably complex and subtle spirit, reminiscent of good eau-de-vie (in the case of young jenever) or even scotch (which aged jenever sometimes resembles).

But gin as most of the world knows it today—cocktail gin—is quite different from Dutch jenever. Its evolution began only a few years after the happy experiment of Dr. Sylvius. English soldiers fighting in the Netherlands saw their Dutch counterparts drinking jenever on the battlefield, and dubbed it "Dutch courage" for the way it seemed to inspire fearlessness. And when they went home, they took it along.

William of Orange, the Dutch stadtholder, all but guaranteed jenever's success when he became King William III of England in 1689: He promptly banned imports of French brandy—France and Holland were at war at the time—and levied high import duties on distilled goods from Germany.

Before long, English distillers were making jenever themselves—and dispensing with some of the fine points of production. English gin of this period was cheap and, by all accounts, rough and potent—and the general population, used to drinking beer, didn't accord it the respect that stronger spirits are due. By the early 18th century, gin had become the scourge of London—"mother's ruin," it was called—fueling poverty, prostitution, and violent crime. Wretched, gin-induced drunkenness, of the kind so memorably depicted by Fielding, Hogarth, and Cruikshank, was commonplace. A famous tavern sign of the time promised customers the chance to get "Drunk for a penny, dead drunk for two pence, straw for nothing." Gin consumption in England is said to have risen from half a million gallons in 1690 to as much as 18 million gallons in 1710.

The imposition of high taxes and other government measures eventually curbed the popularity of cheap gin, and by the mid-19th century, as its association with the lower classes faded into memory, gin found new life as a respectable liquor in the higher levels of society. The original London gin had been sweetened with sugar and drunk straight; by the mid-1800s, it had grown drier and more refined, and was being consumed in gentlemen's clubs and in the Empire's oft-steamy colonial outposts around the world. The English and English-style American gins that are so popular internationally today—brands like Tanqueray, Bombay, Boodles, Beefeater, Gordon's, and Seagram's—are descendants of the so-called London dry gin of this period.

The Pilgrims brought gin to America on the Mayflower (they were English, after all—and they had spent time in Amsterdam before heading for the New World), and it was not unknown in the Colonies during the pre-Revolutionary era. But it was only after World War I, when returning doughboys brought home a taste for the martini—so popular in Paris and London—that gin became an American fad.

There are many theories about the invention of this quintessential cocktail. One has it first concocted in the mid-1800s, in the town of Martinez on the inland side of San Francisco Bay. Another tale suggests that it was an English creation, named—for its kick—after the Martini and Henry rifle used by the British army. Personally, I suspect it had something to do with the famous Italian vermouth, Martini & Rossi. Some bartender (or vermouth salesman) might very well have thought up the thing, and named it for one of its main ingredients.

One thing is sure: The original martini was sweet, made with sweet vermouth (Martini & Rossi or otherwise), in as much as a four-to-one ratio with the gin. A dry version may have been formulated first around the turn of the century in New York—at the old Hotel Knickerbocker on Broadway and 42nd Street—and may have traveled from there to Europe, perhaps on the luxury liners of the time. The years of Prohibition, with their infamous "bathtub gin" (commonly made by flavoring raw alcohol and water with glycerine and juniper juice), didn't do much for gin's reputation in this country. But following repeal in 1933, cocktail hour broke through the barred doors of the speakeasies, and the martini and its friends found their place in American society.

In the past two decades, a perfectly good if rather bland clear-colored spirit known as vodka has outpaced gin in America. Some poor benighted souls even think you can make a martini with it. Good gin, though, with its faint hint of juniper and other herbs and spices (the modern recipe also includes such flavorings as coriander, cardamom, angelica, caraway, cassia, citrus peel, and orrisroot), deftly balances subtlety and true character, and is inherently more interesting than vodka. It's great stuff. I only regret the years I wasted without the pleasure of its acquaintance.