Mary Beth Keane, who brought Typhoid Mary to life in her last novel, “Fever,” was researching another historical novel when, she says, “real life kept intervening in the form of one crisis after another, either in my own family or those of my friends, so it began feeling more and more odd to turn away from the drama of real life just to step into made-up drama of the past.”

She explains, “It was as if I reached 40 and everyone started losing it a little, and I began ‘Ask Again, Yes’” — a contemporary saga of two suburban New York families, which debuts this week at No. 5 — “as a way to write through that.”

Keane says that her parents “were aging and talking about their regrets, couples I thought of as solid were splitting up, people were drinking far too much, losing jobs, risking things we’d all worked so hard to get.” She was particularly affected by her husband’s long estrangement from his parents and began to look for a way to explain that break to their children. “I wanted to help them understand that even people who are decent in their hearts might get lost, might fail to live up to the contract of parenthood or marriage. No one ever plans to become estranged. It happens day by day, year by year, until next thing — oops! — 20 years have gone by. Is it possible for a parent and child to become true strangers to one another? Or is there always some connection? I began writing this book to figure out how I might answer that question.”

Some of the main characters in “Ask Again, Yes” are New York City cops. “I don’t have police officers in my family, which is unusual for an Irish family, I suppose, but growing up in Pearl River, New York, the fathers of many of my friends were cops,” Keane says. “I knew them as sweet, kind men, but I also knew they often wore guns under their clothes. I knew these men sometimes saw violence at work, or even participated in that violence. I think I became a little obsessed with reconciling that contradiction.”