Bernard Lewis, a preeminent scholar of Middle Eastern history whose work profoundly shaped Western views of the region — including fears of a “clash of civilizations” — but also brought scorn from critics who considered his views elitist and favoring Western intervention, died May 19 at an assisted-living facility in Voorhees, N.J. He was 101.

The death was confirmed by his romantic partner and co-author, Buntzie Churchill, who did not cite a specific cause.

Dr. Lewis’s prolific scholarship — including more than 30 books, hundreds of articles and competence in at least a dozen languages — traced fault lines that define the modern Middle East, such as sectarian divisions, the rise of radical Islamists and entrenched dictatorships, some backed by the West.

Along the way, Dr. Lewis often gained a privileged vantage point for events in the region during a life that spanned the era of T.E. Lawrence, oil discoveries in Arabia and showdowns against the Islamic State.

He roamed souks and back streets for British intelligence during World War II; had tea in Golda Meir’s kitchen in honor of his ardent support of Israel; dined with Pope John Paul II; and was hosted in the Peacock Throne court of Iran’s former shah.The London-born Dr. Lewis also built a parallel reputation that spilled far beyond academia. It brought him into the folds of Washington’s power brokers and policy shapers after his move to Princeton University in 1974. So began a period of contrasting trajectories for Dr. Lewis that played out over decades and, in many ways, forged his dual images as either revered or reviled.

Dr. Lewis’s friendship — and ideological kinship — with the Cold War hawk and Israel supporting Sen. Henry M. “Scoop” Jackson (D-Wash.) opened prominent doors in the capital, eventually giving Dr. Lewis favored status among top White House and Pentagon planners before the 2003 invasion of Iraq.

At the same time, Dr. Lewis’s standing was under assault from intellectual rivals, especially in the heated political fallout from the 1973 war that left Arab armies routed by Israel. Dr. Lewis — Jewish by birth and uncompromising in attitude — increasingly became a target of detractors who ridiculed him as an embodiment of Western-centric arrogance and the West’s attempts to remain the big brother of the Middle East.

Even as Dr. Lewis kept up an astonishing pace of writing and interviews into his mid-90s, he was often dogged by questions over his close ties to the architects of the invasion of Iraq, including then-Vice President Richard B. Cheney and two of Jackson’s proteges, then-Deputy Defense Secretary Paul Wolfowitz and security adviser Richard Perle.

Dr. Lewis had no qualms about hard-edge policies toward the Middle East, once famously advising “get tough or get out,” in what some have dubbed the Lewis Doctrine. He repeatedly denied that he backed the invasion of Iraq, saying he advocated for greater aid to Western-allied Kurds in northern Iraq as a counterweight to the Baghdad regime.

“For some, I’m the towering genius,” Dr. Lewis told the Chronicle of Higher Education in 2012. “For others, I’m the devil incarnate.”

But what stood out for many, especially in an age of borderless violence, was Dr. Lewis’s premise of inevitable friction and competition between the Islamic and Western worlds — particularly as Islamist militants and other groups exert more influence. He revived his earlier phrase “clash of civilizations” in an article, “The Roots of Muslim Rage,” in 1990, two years before it was popularized by the late Harvard professor Samuel Huntington.

Dr. Lewis further argued that the Middle East’s troubles were mostly self-inflicted and were not simply inherited ills from colonialism or outside meddling. He praised Islam as a great faith but fretted that it was being hijacked by intolerance and anger.

“He provided intellectual scaffolding for the belief that something was very wrong with Arab societies” and that U.S. support should remain squarely behind Israel, Jacob Heilbrunn, author of “They Knew They Were Right: The Rise of the Neocons,” told the Jewish American magazine Moment in 2011.

Beyond the polarizing arguments in which he was swept up, Dr. Lewis was a man of expansive intellectual appetites. He immersed himself in topics as varied as Sufi mystic poetry and intricacies of Islamic law. Step by step, he crafted a style that combined a professor’s gravitas, a pundit’s wit and a patrician’s confidence, despite his upbringing outside England’s upper crust as the son of a modestly successful Jewish real estate agent and a housewife.

And, like his subjects and prose, Dr. Lewis defied easy definition.

He was, at times, an academic sleuth, poring over ancient Arabic volumes or poking through lonely archives in Turkey. He could quickly shift to become a commentator on present-day issues such as Egypt’s Muslim Brotherhood (“dangerous”), aspects of Saudi Arabia’s Salafist brand of Islam (“extreme and fanatical”) and Iran’s theocracy (“encourage resistance”).

In his works — including back-to-back bestsellers after the 9/11 attacks, “What Went Wrong?” (2002) and “The Crisis of Islam” (2003) — Dr. Lewis increasingly courted a mass audience. He sought to explain Muslim views, but also scolded Western leaders for failing to grasp the reach of groups such as al-Qaeda.

“Osama bin Laden made me famous,” he once quipped.

His tone grew more serious in subsequent years as he warned that the Middle East may increasingly breed radicalism and anti-Western fervor. “Either we bring them freedom or they destroy us,” he wrote in a 2010 book, “Faith and Power.”

Such comments only added fuel to one of academia’s most public feuds.

Another master of Middle East affairs, the late literary critic Edward W. Said, described Dr. Lewis as a peddler of old-school dictums about the need for a strong guiding hand with the region. Said, a humanities professor at Columbia University whose 1978 book “Orientalism” helped establish the academic field of post-colonial studies, called Dr. Lewis an “active policy scientist, lobbyist and propagandist” in a 1982 reply to Dr. Lewis in the New York Review of Books.

Firing back, Dr. Lewis accused Said of spewing an “unsavory mixture of sneer and smear, bluster and innuendo.”

Said’s views mostly gained the upper hand in academic circles, leaving Dr. Lewis overshadowed in many college syllabuses. But he did not surrender. In reply to Said’s belief that only Arab scholars can grasp the Arab mind, Dr. Lewis gave an oft-quoted reply: If Westerners cannot study other cultures, only fish can study marine biology.

Dr. Lewis also withstood criticism for his stance that the slaughter of Armenians starting in 1915 did not meet the strict definition of “genocide.” He acknowledged the huge loss of life among ethnic Armenians in what was then the Ottoman Empire, but he insisted that there was insufficient evidence linking it directly to orders by Ottoman rulers. Estimates vary widely, but between 300,000 and 1.5 million Armenians perished.

Imad Salamey, a professor of political science and international affairs at Lebanese American University in Beirut, said Dr. Lewis considered the Arab world unable to shake off rule by monarchs or strongmen. “Most Arabs don’t accept the perspective — at all,” Salamey said.

Dr. Lewis had many defenders, some of whom cited a 1976 article, “The Return of Islam,” in which he accurately predicted the expanding power of Islamist movements and militants.

“Whatever one thinks of the policies advocated by Lewis — and he really wasn’t a fervent policy advocate — it can’t be denied that he mapped the trajectory of the present-day Middle East in advance,” said Martin Kramer, a professor at Shalem College in Jerusalem and a former student of Dr. Lewis’s at Princeton.

Bernard Lewis was born May 31, 1916, at the height of World War I, whose fallout would include a new map of the Middle Eastcarved out of former Ottoman lands.

By the time of his bar mitzvah, he had become fascinated with history and languages, asking to continue his Hebrew lessons. He had already learned Latin and French and picked up Italian from his opera-loving father. He earned a place in the School of Oriental and African Studies, or SOAS, at the University of London, receiving a bachelor’s degree in 1936 and a doctorate three years later. In between, he made his first trip to the Middle East, reaching Alexandria, Egypt, by boat.

During World War II, Dr. Lewis was drafted into a tank unit. “I didn’t stay there long,” he said of the armored corps, “either because of my aptitude for languages or my ineptitude for tanks.” He moved to intelligence units before being seconded to the Foreign Office. After the war, he was appointed to chair a new Middle East department at SOAS.

Dr. Lewis soon left SOAS to accept a position at Princeton. He took U.S. citizenship in 1982.

While in Istanbul in 1950, Dr. Lewis had a first big break: He was granted access as the first Westerner to view the Ottoman archives.

The founding of Israel in 1948 soon put up roadblocks elsewhere. Arab governments became deeply suspicious of all Jews, even Westerners, and visas were scarce, shutting him out of firsthand research for decades in many places.

It did not stop his pen. “The Arabs in History” (1950) and “The Middle East and the West” (1964) helped cement his academic standing. His 1961 book “The Emergence of Modern Turkey,” is still hailed as a gold standard on the subject.

This year, the Israeli government named Dr. Lewis one of the 70 “greatest American contributors to the U.S.-Israel relationship” for the country’s 70th anniversary.

His marriage to Ruth Hélène Oppenhejm ended in divorce. Besides Churchill, of Princeton, N.J., survivors include two children from his marriage, Melanie Dunn of Onset, Mass., and Michael Lewis of Potomac, Md.; seven grandchildren; and three great-grandsons.

In the 1970s — amid Lebanon’s civil war and Iran’s looming Islamic revolution — Dr. Lewis turned increasingly to studies of militant Islam. He reached Princeton’s mandatory retirement age of 70 in 1986 and stayed on as a professor emeritus.

In his crowning volume, “Notes on a Century” (2012), his once-solid optimism about the future of the Arab world and the West’s ability to spur restructuring seemed shaken.

“Our politics and diplomacy are not welcome,” he told the pan-Arab newspaper Asharq al-Awsat after the book’s publication, “though our weaponry and money are.”

Hugh Naylor in Beirut contributed to this report.