For the first time, middle-aged men and women are the largest, most influential, and richest segment in the country. Floating somewhere between 40 and 64, they constitute one-third of the population and control nearly seventy percent of its net worth. In booms and recessions, a trillion-dollar economy feeds and fuels their needs, whims, and desires. Better-educated and healthier than their predecessors, these early and late midlifers are happier, more productive, and more involved than any other age group. Women are part of the first generation to enter their 40s and 50s after the feminist movement, and they have options that their mothers and grandmothers could barely imagine.

Life spans have increased as scientific advances have overcome many of the body’s once-unavoidable limitations. Viagra has recharged the sex lives of middle-aged men. Beauty treatments like Botox and facial fillers can erase the stigmata of facial wrinkles. New surgical procedures and recuperative strategies for worn-out knees and creaky rotator cuffs allow aging bodies to ski moguls and surf twenty-footers.

Yet if this is the best possible moment to be middle-aged, why then is this period of life still commonly greeted with resignation or regret, disappointment or evasion? No one is eager to show off the AARP membership card that arrives in the mail unbidden shortly before you turn fifty. Birthday congratulations are replaced with jokes about hearing loss, plunging libidos, and afternoon naps. Middle age is a punch line.

(Also)  Middle age is a “cultural fiction,” constructed differently around the globe, says Richard A. Shweder, a University of Chicago anthropologist. Outside America and Europe, middle age is often defined by one’s position in the family. Hindu women in the Indian state of Orissa have a term—prauda—for the period when a married woman takes over the household, but not for middle age. In Samoa, where birthdays are seldom celebrated, there is no word for midlife; instead tagata matua is used to denote a person of maturity and good judgment.

I thought about our cultural fiction one sun-bleached afternoon while sitting on a beach with some friends, all of us past 40. As our children busied themselves building crab condominiums in the sand, we talked about the cycle of our lives, the opportunities and experiences we had compared with our parents and grandparents. According to the calendar, we were in middle age, but that was not at all the way we felt. For those of us born after World War II, the middle age we inherited did not fit quite right.

We slipped our arms into the sleeves, but middle age pretty much hung there, heavy and oversized, like a bulky, drab woolen greatcoat. The oldest members of the baby boom generation have been trying to tailor midlife to suit them better, but it still feels like a hand-me-down. When my mother watched me play in the sand, she was in her 20s. By the time she reached middle age, I was finishing up graduate school and traveling. I married at 39, became a parent at 40, and still thought about what I wanted to do when I grew up. Some of my friends were on my mother’s timetable, while I was checking out preschools and shopping for tricycles.

Considering how dramatically the experience of middle age had shifted in one generation, I wondered what it was like even further back. I wanted to examine how specific ideas about midlife were created and why one won out over another. When the average life expectancy was 40, did people think of 20 or 25 as middle age? Now that it is pushing past 80, has the traditional 40-year-old starting line moved forward? Before the twentieth century, did Americans view the middle years as a time of decline and retrenchment, a prelude to death? Did they lie about their age to make themselves seem younger? Were women embarrassed about creases around their mouths? Did men fret about the first gray hair? How is it that midlife is portrayed simultaneously as crisis-ridden and dully uneventful? Despite a freighter’s worth of books written about midlife, hardly any explore its history in depth.

This book is a biography of the idea of middle age from its invention in the second half of the nineteenth century to its current place at the center of American society, where it wields enormous economic, psychological, social, and political power. This stage’s advent has generated an unfamiliar landscape of possibilities, creating new conceptions of ourselves, our business opportunities, and our avenues of social control.

Patricia Cohen has been a New York Times reporter for thirteen years. She has also worked at The Washington Post, new York Newsday and Rolling Stone. She has a BA from Cornell University and a graduate degree from the Woodrow Wilson School at Princeton University. Her book can be found @ http://www.strandbooks.com/new-arrivals/in-our-prime-the-invention-of-middle-age. She can also be found @ patcohen.wordpress.com.