There is nothing quite like falling in love. The palms sweat, the heart races. But time passes, and, nights of endless passion are replaced with snoring. Studies show that married couples can expect around two years of the passionate stuff, and then decades of a companionable slog. So why get married at all? Why not just look for the next dopamine hit?
    It is a good question. Many are clearly asking it, as nearly nine in ten people live in a country with a falling marriage rate. In search of answers, Aziz Ansari, an American comedian, teamed up with Eric Klinenberg, a sociologist at New York University, to write Modern Romance, a lively look at love, marriage and the oddities of mating in the 21st century.
    The pursuit of love has never before involved so many choices, with so many new-fangled tools and such high expectations. Dating apps and social networking sites ensure that anyone with a smartphone can sample from a seemingly endless buffet of romantic prospects. This makes being single more enjoyable, but also more stressful.
    Digital wooing helps people to behave like scoundrels. Among the hundreds of people interviewed for <em>Modern Romance</em>, many admitted to becoming addicted to dating sites. One woman confessed to having hunted for better-looking alternatives while enroute to a first date. Others talked about the ease of starting affairs or snooping on partners. Countless women complained of receiving messages from aspiring Lotharios that ranged from lewd to asinine. Requests to "hang out" do not make the heart go aflutter.
    The book treads more novel territory when it considers mating rites farther afield. In Qatar, where the only way for a woman to leave her family's home is "to get married or die" (in the words of one woman), the Internet affords more freedom to socialise away from prying eyes. In Japan, where a sluggish economy has left men feeling more insecure, few can pluck up the nerve to ask women out. This has ensured a booming "relationship replacement" industry, in which women are paid to serve drinks and listen attentively.
    Readers should not expect a serious work of sociology, but a breezy survey of the relevant research. But when it comes to the question of marriage, Mr. Ansari reaches a satisfying conclusion. Certainly, fewer people are tying the knot, in part because fewer people need to, and the plethora of potential mates raises the opportunity cost of choosing one. But people in good marriages statistically live longer, happier and healthier lives. The passion may burn up, but a more stable, more trusting love takes its place—and this kind of love only gets stronger with time.  Today's complicated situation of hunting for love is ______.