Karl E. Meyer, a longtime journalist for The Washington Post and New York Times who wrote about Fidel Castro’s rise to power in Cuba and later was the author of books about international relations, archaeology and the worldwide illicit trade in artistic treasures, died Dec. 22 at a hospital in New York City. He was 91.

The cause was prostate cancer, said his wife, Shareen Blair Brysac.

Mr. Meyer was a third-generation journalist who also possessed a doctorate in politics from Princeton. He brought a scholarly approach to his assignments as a foreign correspondent, editorial writer and author, as well as a keen understanding of leadership and changing political currents.

During his eight years as an editorial writer for The Post, from 1956 to 1964, he often took time out for long reporting trips, particularly in Latin America. On a three-week journey through Cuba in 1958, often on horseback, he chronicled Fidel Castro’s rise to power as a charismatic guerrilla leader.

“About Fidel Castro, the leader of the shooting opposition in the distant Sierra Maestra,” Mr. Meyer wrote, “you find a variety of opinions in the middle-class world of Cuba.

“The attitude varies from idolatry to criticism and distrust. . . . None feel he is a Communist, but they worry about his possible ‘immaturity.’ ”

More than a year later, after Castro and his youthful followers had seized control of the country, Mr. Meyer returned to Cuba for an assessment: “There are few cases in history in which leaders so young have attempted to do so much so soon. The results, however, are not always happy.”

Mr. Meyer was among the first journalists to report on the Bay of Pigs invasion, a failed attempt to depose Castro in 1961. A year later, Mr. Meyer co-wrote a book with journalist Tad Szulc, “The Cuban Invasion: The Chronicle of a Disaster,” about the Bay of Pigs fiasco.

In 1963, according to Chalmers M. Roberts’s “In the Shadow of Power: The Story of The Washington Post,” Mr. Meyer was called on to write a particularly sensitive editorial after the newspaper’s publisher, Philip L. Graham, died by suicide.

“His rangy figure and quicksilver wit were as familiar a part of our enterprise as the fonts of type in our composing room,” Mr. Meyer wrote. “In all that he dealt with at The Washington Post and its related ventures, he was broadly liberal, eminently practical and endowed with an intuitive grasp of coming needs.”

From 1965 to 1970, Mr. Meyer was based in London, writing about European politics and culture for The Post. In 1969, he found himself in Amsterdam after midnight, compiling what he called “an uncensored report on a wanton Saturday night in the most uninhibited” club in the city, where young patrons smoked hashish, danced and sometimes disrobed while pornographic films flickered on the walls.

“The most shocking revelation about Amsterdam’s most notorious club,” he wrote, “is that it was a bore, a Dionysian evening at which the god of orgies yawned himself to sleep.”

While working as a journalist, Mr. Meyer also found time in the 1960s to write books on U.S. politics and Cuba. During the 1970s, he wrote two books on archaeology, including “The Plundered Past” (1973), in which he described an international market for stolen artwork and historical artifacts. He revealed an underground network of smugglers, including the discovery that a New York dealer built an airstrip in Mexico to fly out the intact facade of a Mayan temple, obtained through bribes and subterfuge.

“Every archaeological site is like a time capsule,” Mr. Meyer wrote. “When such a time capsule is destroyed, either by a looter or a bulldozer, the loss is total. One cannot grow another Indian mound.”

He returned to journalism in 1975 as an editor and television critic for the weekly Saturday Review, then served on the Times editorial board from 1979 to 1998 and later as editor of World Policy Journal until 2008.

After the attacks of Sept. 11, 2001, Mr. Meyer warned of a growing religiosity in international relations, both in the United States and abroad.

“The new factor in American politics is the emergence of a politically powerful Christian right,” he told the Times in 2002. “It worries me, as I worry about the rise of militant Islam or Hindu nationalism. These are all variations of the same problem. They seek a theological sanction for secular foreign policy choices.”

Karl Ernest Meyer was born May 22, 1928, in Madison, Wis. His grandfather was the editor of a German-language newspaper in Milwaukee, and his father, Ernest L. Meyer, was a columnist and editor for the Madison Capital-Times and later the New York Post. His mother was a homemaker.

(He was not related to Eugene Meyer, who purchased The Washington Post in 1933 and whose daughter, Katharine Graham, later led the newspaper as publisher and chief executive.)

Mr. Meyer completed high school in New York City and graduated in 1951 from the University of Wisconsin, where he edited the student newspaper and a literary magazine. He was a reporter at the Times before attending graduate school at Princeton University, where he received a master’s degree in public administration in 1953 and a doctorate in politics in 1956. He was a visiting professor at several colleges, was a member of the Council on Foreign Relations and, in 1990, edited a collection of historical newspaper columns, “Pundits, Poets, and Wits.”

His first marriage, to Sarah Peck, ended in divorce. Survivors include his wife since 1989, dancer, journalist and author Shareen Blair Brysac of Manhattan and Weston, Conn.; three children from his first marriage, Ernest Meyer of Sacramento, Jonathan Meyer of Brooklyn and Heather Meyer of London; a sister; and three granddaughters.

Mr. Meyer’s most recent, book, written with Brysac, was “The China Collectors: America’s Century-Long Hunt for Asian Art Treasures” (2015). Critic Michael Dirda, writing in The Post, called it an “excellent book, which tracks the adventures of the learned, cutthroat and eccentric scholars and collectors who brought the treasures of the Middle Kingdom to America.”

In several other books, including “The Dust of Empire” (2003), “Tournament of Shadows” (1999) and “Kingmakers” (2008) — the latter two written with his wife — Mr. Meyer warned of what he called “the unintended consequences of empire” when Western powers become involved in the political and economic affairs of Central Asian countries, including Afghanistan and Iran.

“History is not a blueprint but a cautionary tale,” he wrote in “The Dust of Empire.” “It is replete with warnings to those who believe that they can outguess the future, or that their country has a mandate from providence, or that alliances are a nuisance, or that a brusque arrogance is preferable to simulated humility.”