Allan Metcalf, a renowned popular writer on language, here traces the evolution of America's most popular word, writing with brevity and wit, and ranging across American history with colorful portraits of the nooks and crannies in which OK survived and prospered. He describes how OK was born as a lame joke in a newspaper article in 1839--used as a supposedly humorous abbreviation for oll korrect (ie, all correct )--but should have died a quick death, as most clever coinages do. But OK was swept along in a nineteenth-century fad for abbreviations, was appropriated by a presidential campaign (one of the candidates being called Old Kinderhook ), and finally was picked up by operators of the telegraph. Over the next century and a half, it established a firm toehold in the American lexicon, and eventually became embedded in pop culture, from the I'm OK, You're OK of 1970's transactional analysis, to Ned Flanders' absurd Okeley Dokeley! Indeed, OK became emblematic of a uniquely American attitude, and is one of our most successful global exports.