Musing poignantly on time, money, success, failure, the divine, and the earthly, James Atlas has plumbed his fears of becoming obsolete. The biographer and editor has settled reluctantly into middle age, capturing the process in “My Life in the Middle Ages: A Survivor’s Tale” (HarperCollins), a series of essays about the acceptance of growing older.

His cozy, three-person publishing office is nestled amid those of a Midtown law firm, where he has participated in a small reading group: He and the attorney next door read “Pride and Prejudice.” Seated in his impeccable workplace, Mr. Atlas described the genesis of his book. It originated as a New Yorker magazine assignment. “Tina [Brown] got the idea that there was no fun any more, and people were working too hard.” Ms. Brown thought that although he was no longer in his freewheeling youth, Mr. Atlas still knew how to have a good time. She was right.

Asked if he has led a privileged life, “Easy no, privileged yes.”

“My Life in the Middle Ages” begins with a chapter on his parents. Mr. Atlas’s paternal grandfather ran a drugstore, and Mr. Atlas ran the cash register and read “Classic Comics” like Dostoevsky in his downtime. His father was a general practitioner near Chicago. Like his father, was the son also a sort of generalist – as wide-ranging journalist and “general” editor of biographies? “Except I don’t cure anybody,” Mr. Atlas said.

Mr. Atlas recalled the teenage thrill of discovering the work of Saul Bellow, about whom he would later write a biography. While traveling to Europe with his parents, Mr. Atlas bought “Dangling Man.”

“That voice,” he marveled. “Literature was supposed to be about Paris; it turns out you could write this stuff about your own city, Chicago.”

The next development came at Oxford: Mr. Atlas learned from eminent Joyce biographer Richard Ellmann “that you could be an ordinary person and write about geniuses who were ordinary people.”

Biography is important, Mr. Atlas said, because “We live in a chaotic transitional period.” Readers want to understand the story behind the story, he said.

“Books are just too long,” Mr. Atlas said, adding, “Not my books – others’ books.” When he reached page 1,000 in writing his monumental analysis of Bellow, Mr. Atlas laminated the sheet and gave it to his editor.

Following his own advice, Mr. Atlas in 1999 launched Penguin Lives, a series that personalities as varied as Joan of Arc and Elvis. “I was reading a short biography, I don’t remember which one – I keep changing it – when I got the idea ‘short books by distinguished authors.'” Investment banker Ken Lipper, a former deputy mayor, became his business partner on the project. After Mr. Lipper advised him not to share the idea with others, Mr. Atlas later told his wife. “I think I’ve just had a venture capital moment.”

With new backers, other series of relatively short biographies followed since December 2002. So far, one has focused on great figures (“Eminent Lives”) and another covers American history. Both are published by Harper-Collins. He worked with W.W. Norton on a science and a business series.

His future projects? “I’m kind of depleted right now,” he said, but he wants to write a book of essays about work, friends, and art; a literary memoir to be titled “The Shadow and the Garden,” and a book on the history of biography starting with Suetonius and Plutarch and extending to the present.

Although the series of biographies is a relatively recent development, Mr. Atlas has a long-standing interest in documenting the lives of others – with varying degrees of success.

While living in Cambridge, Mass., the city where he graduated from college and edited the Harvard Advocate, he wrote about pill-popping wunderkind poet Delmore Schwartz. Mr. Atlas survived off a modest legacy from his grandfather. He recalled a phrase of oral historian Studs Terkel: “But the dough went.”

He next plunged into New York journalism. He joined Time magazine in 1977, working with Michiko Kakutani, Graydon Carter, and Walter Isaacson. “I was a floater. Every Monday, they posted on a bulletin board what you worked on. Mr. Atlas added, “I was a failure at Milestones,” a section marking life events of notable figures such as death and divorce.

At the New York Times Book Review, he sat amidst “large ziggurats” of books and filed reports. Sliding over to that paper’s magazine, he said, “was fun. I didn’t know it at the time so I left.” He joined the Atlantic Monthly, then became a contributing editor at Vanity Fair, before returning to the New York Times Magazine for a decade (“a tough job that became interesting”).

During those years, Philip Roth was the most vivid presence he was ever to encounter: “a combination of Henny Youngman and Flaubert.” His worst interview subject was V.S. Naipaul. “I took out a small tape recorder and he said, ‘Put that away. It makes you lazy.’ It went downhill from there – steeply. I never knew anybody to have the courage to be as unpleasant as he did.”

Mr. Atlas reflects philosophically on not having written the official biography of Parnassian critic Edmund Wilson, which he was commissioned to write. The problem he faced was Wilson had already described it all in his journals. “I felt like a custodian, just sweeping up” and putting things into tidy piles.