Our language is full of hundreds of quotations that are often cited but seldom confirmed. Ralph Keyes's The Quote Verifier considers not only classic misquotes such as "Nice guys finish last," and "Play it again, Sam," but more surprising ones such as "Ain't I a woman?" and "Golf is a good walk spoiled," as well as the origins of popular sayings such as "The opera ain't over till the fat lady sings," "No one washes a rented car," and "Make...