In 1950, four million people in this country lived alone. These days, there are almost eight times as many, thirty-one million. Americans are getting married later than ever (the average age of first marriage for men is twenty-eight), and bailing on domestic life with alacrity (half of modern unions are expected to end in divorce). Today, more than fifty per cent of U.S. residents are single, nearly a third of all households have just one resident, and five million adults younger than thirty-five live alone. This may or may not prove a useful thing to know on certain Saturday nights.