In the winter of 1928, John Maynard Keynes composed a short essay that took the long view. It was titled "Economic Possibilities for Our Grandchildren," and in it Keynes imagined what the world would look like a century hence. By 2028, he predicted, the "standard of life" in Europe and the United States would be so improved that no one would need to worry about making money. "Our grandchildren," Keynes reckoned, would work about three hours a day, and even this reduced schedule would represent more labor than was actually necessary.

Keynes delivered an early version of "Economic Possibilities" as a lecture at a boys' school in Hampshire. He was still at work revising and refining the essay when, in the fall of 1929, the stock market crashed. Some might have taken this as a bad sign; Keynes was undeterred. Though he quickly recognized the gravity of the situation—the crash, he wrote in early 1930, had produced a "slump which will take its place in history amongst the most acute ever experienced"—over the long run this would prove to be just a minor interruption in a much larger, more munificent trend. In the final version of "Economic Possibilities," published in 1931, Keynes urged readers to look beyond this "temporary phase of maladjustment" and into the rosy beyond.

According to Keynes, the nineteenth century had unleashed such a torrent of technological innovation—"electricity, petrol, steel, rubber, cotton, the chemical industries, automatic machinery and the methods of mass production"—that further growth was inevitable. The size of the global economy, he forecast, would increase sevenfold in the following century, and this, in concert with ever greater "technical improvements," would usher in the fifteen-hour week.

To Keynes, the coming age of abundance, while welcome, would pose a new and in some ways even bigger challenge. With so little need for labor, people would have to figure out what to do with themselves: "For the first time since his creation man will be faced with his real, his permanent problem—how to use his freedom from pressing economic cares, how to occupy the leisure, which science and compound interest will have won." The example offered by the idle rich was, he observed, "very depressing"; most of them had "failed disastrously" to find satisfying pastimes. In particular, he pointed to the "wives of the well-to-do classes" in the United States and England, who, "deprived by their wealth" of traditional occupations, like cooking, were "quite unable to find anything more amusing" to do. As a greater and greater proportion of the population found themselves liberated from work, Keynes worried that society might suffer from a sort of generalized "nervous breakdown." It was those who could appreciate "the art of life itself," he wrote, who would "be able to enjoy the abundance when it comes."

Four-fifths of the way through Keynes's century, half of his vision has been realized. Since "Economic Possibilities for Our Grandchildren" was published, the U.S. gross domestic product has grown, in real terms, by a factor of sixteen, and G.D.P. per capita by a factor of six. And what holds for the United States goes for the rest of the world, too: in the past eighty years, the global economy has grown at a similar rate.

But if we have become, in aggregate, as rich as Keynes imagined, this wealth has not translated into leisure. (When was the last time someone you know complained about having too little to do?) In terms of economic theory, this is puzzling. In terms of everyday life, it's enough to, well, induce a nervous breakdown.

Brigid Schulte, a reporter for the Washington Post, is the latest author to tackle the question—very loosely speaking—of where Keynes went wrong. In "Overwhelmed: Work, Love, and Play When No One Has the Time" (Sarah Crichton Books), she explores why it is that twenty-first-century Americans feel so swamped.

Schulte begins "Overwhelmed" by trying to measure her own leisure, or lack thereof. She enlists the help of John Robinson, a sociologist at the University of Maryland who's an expert on time use. Robinson instructs Schulte to keep a time diary and provides her with a handy Excel template. But Schulte finds that her time is too "unruly" to fit the template's neat little rectangles, so instead she decides to record her days in little black notebooks. One afternoon, when she is eating lunch at her desk while waiting on hold with the pharmacy that supplies her son's EpiPens and searching the Web to figure out how to obtain a death certificate for her brother-in-law, who has died in China, she calls Robinson to ask him how to classify this sort of activity. Robinson tells her just to keep filling in her diary and he will sort things out. When she presents him with her pile of little black notebooks, however, he balks. They're impossible to read, much less analyze. "What's this word?" he asks, pointing to an entry from 2 A.M. on September 16th.

"Panic," Schulte tells him. " 'Wake in a panic.' "

With the question of her own leisure left unresolved, Schulte decides to head to Paris for the annual meeting of the International Association for Time Use Research. ("There's great interest in trying to understand why time pressure is increasing," a sociologist from Oxford tells her. "This is the hot topic in time research right now.") She visits the Yale Stress Center, in New Haven; meets with overstressed mothers in Portland, Oregon; and sits in on a focus group in Fargo, North Dakota. "Life is stressful in Fargo," the organizer of the group says. Ostensibly in an effort to reduce her own stress, Schulte attends a trapeze academy and leaps off a platform twenty feet high. Along the way, she discusses various possible explanations for what she likes to call "the overwhelm," as if it were something outside of us, like the Arctic or the Amazon.