Nobody reads a reference book to be amused, much less charmed. Useful though they are, the vast majority of dictionaries and encyclopedias are poker-faced pieces of work that stick to the facts and present them as soberly—and unstylishly—as possible. One of the reasons why this is so is that such books tend to be written not by individuals but by panels of experts. Try to imagine a joke written by a committee and you'll get the idea.

He wasn't kidding. Look up "Evolution," for example, and you'll find this 1925 statement by the Bible-thumping evangelist Billy Sunday: "If a minister believes and teaches evolution, he is a stinking skunk, a hypocrite, and a liar." Look up "Critic" and you'll be confronted with a rich catalog of ripe insults, among them this passage from Samuel Coleridge's "Modern Critics": "All enmity, all envy, they disclaim, / Disinterested thieves of our good name: / Cool, sober murderers of their neighbor's fame." Or check out "Irish," under which can be found no less than a page of invidious comments, including a sideswipe from, of all people, Gerard Manley Hopkins: "The ambition of the Irish is to say a thing as everybody says it, only louder."

Most delightful of all are the proverbs. According to Mencken, "Special attention has been given to the proverbs of all peoples, for in them some of the soundest thinking of the human race is embodied, and also some of the most pungent wit." No doubt, but Mencken is widely suspected to have coined a considerable number of them himself. The entry on "Marriage," for instance, ends with a page and a half of anonymous witticisms, including this "German proverb": "The bachelor is a peacock, the engaged man a lion, and the married man a jackass." I wouldn't be even slightly surprised if that particular "proverb" turned out to be the work of the waggish editor of the "New Dictionary of Quotations."