Each loss meant that Mary had to work harder. To help pay expenses after her father’s death, she got after-school jobs. In one of those jobs, as a switchboard operator at the Shelton Hotel in Manhattan, she eavesdropped on inhabitants, including Tennessee Williams — who, she noted in her memoir, had the cheapest room in the hotel, at $30 a month.

In listening to his conversations, Ms. Higgins Clark wrote, “I didn’t hear anything that fascinated me.”

“Years later,” she wrote, “when a mutual friend gave Williams a copy of the manuscript for ‘Where Are the Children?,’ which had just sold to Simon & Schuster, his comment was, ‘I have a lot of friends who can write better than that,’ so I guess I didn’t fascinate him either. We’ll call it a draw.’”

She and Warren Clark, from her neighborhood in the Bronx, fell in love, and he proposed on their first date. They determined that she should continue with her plan to become a flight attendant for Pan Am and planned a wedding for the next year, 1949.

Although she had begun pitching her first short stories to confession magazines when she was 16, Ms. Higgins Clark endured a rain of rejection slips for the next several years before she sold her first story, “Stowaway,” to Extension magazine in 1956. By then she had three children: Marilyn, Warren Jr. and David. The fourth, born in 1956, was named Carol for a character in that story. The youngest, Patricia, was born in 1958.

After 14 years of a marriage, Warren Clark, who worked in the shipping and airline industries, died of a heart attack in 1964, when Ms. Higgins Clark was 37. Soon she was looking for a job again, but she did not abandon her fiction writing. She rose before dawn to churn out pages while her children slept, then car-pooled to Manhattan to work at the Gordon R. Tavistock advertising agency.

Her first novel, “Aspire to the Heavens” (1969), was not about a murderous psychopath or a jealous friend bent on bloody revenge, but rather about George and Martha Washington. It failed to make a splash, but was republished in 2002 as “Mount Vernon Love Story” and joined the other Higgins Clark titles on the best-seller lists.