The Mirth of Nations is a social and historical study of jokes told in the principal English-speaking countries. It is based on use of archives and other primary sources, including old and rare joke books. Davies makes detailed comparisons between the humor of specific pairs of nations and ethnic and regional groups. In this way, he achieves an appreciation of the unique characteristics of the humor of each nation or group.

A tightly argued book, The Mirth of Nations uses the comparative method to undermine existing theories of humor, which are rooted in notions of hostility, conflict, and superiority, and derive ultimately from Hobbes and Freud. Instead Davies argues that humor merely plays with aggression and with rule-breaking, and that the form this play takes is determined by social structures and intellectual traditions. It is not related to actual conflicts between groups. In particular, Davies convincingly argues that Jewish humor and jokes are neither uniquely nor overwhelmingly self-mocking as many writers since Freud have suggested. Rather Jewish jokes, like Scottish humor and jokes are the product of a strong cultural tradition of analytical thinking and intelligent self-awareness.

The volume shows that the forty-year popularity of the Polish joke cycle in America was not a product of any special negative feeling towards Poles. Jokes are not serious and are not a form of determined aggression against others or against one's own group. The Mirth of Nations is readable as well as revisionist. It is written with great clarity and puts forward difficult and complex arguments without jargon in an accessible manner. Its rich use of examples of all kinds of humor entertains the reader, who will enjoy a great variety of jokes while being enlightened by the author's careful explanations of why particular sets of jokes exist and are immensely popular. The book will appeal to general readers as well as those in cultural studies.