Herbert J. Gans, an eminent sociologist who studied urban and suburban life in America, died on April 21 at his home in Manhattan. He was 97.

A refugee from Nazi Germany, he became one of the nation’s most influential social critics. He taught at Columbia and other leading universities for 54 years, wrote a dozen books and hundreds of articles that shaped the thinking of government and corporate policymakers, colleagues in sociology, and a wide public audience.

Leonard Zeskind, who tracked right-wing hate groups and who foresaw that anti-immigrant ideologies would move to the mainstream of American politics, died on April 15 at his home in Kansas City, at 75.

Mr. Zeskind spent decades studying white nationalism, documenting how its leading voices had shifted their vitriol from Black Americans to nonwhite immigrants. His 2009 book, Blood and Politics: The History of the White Nationalist Movement From the Margins to the Mainstream, resulted from years of following contemporary Klansmen, neo-Nazis, militia members, and other right-wing groups. His investigations earned him a MacArthur “genius grant” in 1998.

At a 2018 town hall meeting in Washington, Mr. Zeskind called on Democrats in Congress to oppose a bill sponsored by Rep. Steve King of Iowa to end birthright citizenship — that anyone born in the United States is a citizen — a focus of anti-immigrant groups warning of threats to the “white race.”           Recently, his book was one of 381 removed from the U.S. Naval Academy library in a purge of titles about racism and diversity, The New York Times reported.

Andrew Gross, a member of a prominent New York apparel family who abandoned a career in the so-called rag trade to write nearly 20 crime and political thrillers, including five with James Patterson that hit No. 1 on The New York Times best-sellers list, died April 9 at his home in Purchase, NY. He was 72.

Mr. Gross was a grandson of Fred P. Pomerantz, the founder of Leslie Fay Inc., whose dresses and sportswear were being sold in more than 13,000 stores around the country when Mr. Pomerantz died in 1986. For a time, Mr. Gross served as senior corporate vice president of the company, until he announced to his wife and three children that he wanted to write a novel. Although the finished novel was never sold, the work came to the attention of Mr. Paterson.

In 2018, Mr. Gross published what he considered his most personal work, Button Man, loosely autobiographical, about a man from a poor Jewish family on the Lower East Side of Manhattan who fight his way up the corporate ladder and into conflict with mobsters. “It is a tribute to my grandfather,” Mr. Gross told Publishers Weekly, referring to Mr. Pomerantz. “He was as tough as any gangster, single-minded and driven. He set a high bar for himself, and he succeeded.”

Joel Krosnick, the longtime cellist of the Juilliard String Quartet, who helped shape its championing of new American music as much as its commitment to the classics, died on April 15 at his home in Hastings-on-Hudson, NY. He was 84.

Mr. Krosnick joined the Juilliard in 1974 and remained until his retirement in 2016. With his longtime musical partner, the pianist Gilbert Kalish, Mr. Krosnick also had an active solo career, giving recitals in the United States and Europe.

Robert B. Shapiro, as former law professor turned corporate executive who performed a marketing miracle by branding aspartame as the sugar substitute NutraSweet, and making it a household name that consumers demanded in thousands of products, died on May 2 at his home in Chicago. He was 86.

Aspartame was invented by chemists at the pharmaceutical company G.D. Searle. In 1985, Searle sold $700 million worth of aspartame, identified as NutraSweet, to dieters and others wanting to avoid sugar. The product has no calories and, in spite of its name, no essential nutritional value,

Margot Friedländer, a Holocaust survivor who, after decades in New York City, returned in 2010 to Berlin, where she found new purpose as a champion of Holocaust remembrance, died on May 9 in Berlin. She was 103.

Mrs. Friedländer and her husband arrived in New York in 1946, vowing never to return to the country that had murdered their families. But after her husband’s death, Mrs. Friedländer decided to go back to see what was left. She had signed up for a memoir-writing class, and had begun to tell her story, which was becoming a memoir. A filmmaker heard about the memoir, and he encouraged her to return to Berlin, where she found her voice. She traveled to schools and talked to young people about how she had survived before her capture and her time at Theresienstadt in Bohemia.