Barbara Tuchman, 77, the author of highly readable and immensely popular volumes of history and biography who won Pulitzer prizes in 1963 for "The Guns of August" and in 1972 for "Stilwell and the American Experience in China, 1911-1945," died yesterday at a hospital in Greenwich, Conn., after a stroke. Mrs. Tuchman's latest work, "The First Salute," a book concerning the American Revolution, has been on various best seller lists for weeks. Among her other notable and popular books is "The Zimmerman Telegram," a 1958 book that concerned actions taken by the German foreign ministry that led to the United States' entry into World War I. Her 1966 book, "The Proud Tower," was the story of the United States and Europe before World War I, and her 1978 book, "A Distant Mirror: The Calamitous 14th Century," was a view of the era through the prism of the life of the great feudal lord Enguerrand de Coucy VII. In addition two Pulitzers for general nonfiction, she was awarded the Gold Medal for History of the American Academy and Institute of Arts and Letters in 1978. Mrs. Tuchman once told an interviewer that "I belong to the 'how' school rather than the 'why.' I am a seeker of the small facts, not the big explanation; a narrator, not a philosopher." But`she was more than that. She took historical topics that were ignored by the average reader and breathed life into them. Topics that professional historians may have known and written about for specialists were transformed by her pen for the average reader into great modern sagas, with the thrill and excitement of the best stories. Her work was written in a brilliant and lucid style, showing the enthusiasm of a gifted amateur and more than a little of the diligence and dedication of a professional historian. Mrs. Tuchman, who lived in Cos Cob, Conn., was born Barbara Wertheim in New York City on Jan. 30, 1912. She was a granddaughter of the businessman and banker Henry Morgenthau Sr. and a niece of Henry Morgenthau Jr.,`who served as treasury secretary under Franklin D. Roosevelt. Her father was Maurice Wertheim, a noted banker and publisher. Mrs. Tuchman graduated from Radcliffe College, where she wrote her honors thesis on "The Moral Justification of the British Empire" in 1933. A year later, she began a professional writing career of sorts as a research assistant with the Institute of Pacific Relations, working for that organization in New York City and Tokyo. In 1935, she joined The Nation magazine, then owned by her father, writing editorials and signed feature pieces. In 1937, the magazine sent her to Madrid to cover Spain's bloody civil war. In 1938, her first book, "The Lost British Policy," appeared. By 1939, she was back in this country and working as a U.S. correspondent for a British magazine called the New Statesman and Nation. During World War II, she was an editor of news from the Far East with the Office of War Information. She then devoted herself to life as a wife and mother. Then in 1956, her second book was published. "Bible and Sword; England and Palestine from the Bronze Age to Balfour" sought to explain the background of the famous 1917 Balfour Declaration. The declaration stated that the British government, with some reservations, viewed with favor the establishment of a Jewish homeland in Palestine. Her third book, "The Zimmerman Telegram," was an enormous popular and critical success. Its thesis was that this country's entry in World War I could be explained by the famous telegram sent by German foreign minister Arthur Zimmerman to the German minister in Mexico. The telegram suggested that if Mexico went to war against the United States, Germany would see that it was compensated with territory in the southwest United States. Mrs. Tuchman popularized a tale that, although perhaps known to professional historians, probably had never been pulled together in such a brilliantly readable way. Unlike many popular histories, the book was not rewritten from previously published material, but relied on primary research for much of its material. These trends continued in Mrs. Tuchman's third book, "The Guns of August," which was a gripping account of the world's plunge into the Great War. It told of the diplomatic maneuvers of August 1914 in which the old Europe almost carelessly slipped to its doom. It also recounted the opening military moves on the Western Front, the invasion of Belgium and the first Battle of the Marne in early September 1914. Mrs. Tuchman researched the book by marching across the battlefields of the front and examining primary material on two continents. The book was a main selection of the Book of the Month Club and won accolades from readers and critics alike. President Kennedy was so taken with it that he gave copies to visiting foreign dignitaries as gifts. "The Proud Tower" was not as popular with critics or readers. Intended as a look at the Western world before World War I, it seemed to some a quirky, disjointed affair. But others found it a brilliant group of essays that looked at the era by examining the Salisbury Tory government of Britain, France at the time of Dreyfus, and the European anarchist movement. It also looked at the United States, stopping to examine the House of Representatives as presided over by Speaker Thomas B. Reed (R-Maine) and such new empire builders as Theodore Roosevelt. "A Distant Mirror" brought to life an obscure and faraway chapter of world history. Yet, even Mrs. Tuchman confessed to troubles writing a book with an almost unknown central character. Probably only she could have written a best seller on those days. Her "Stilwell" book was a masterful biography of Joseph Warren (Vinegar Joe) Stilwell, the gifted, complex and irrascible four-star army general who commanded the Allied armies against the Japanese from China in World War II. He left China during the war after having a falling out with Chinese Nationalist leader Chiang Kai-Shek. While both her 1984 work, "The March of Folly: From Troy to Vietnam," and "The First Salute" were best sellers, they were not critical successes. Some historians pointed out, especially of her second work, that her history was just flat wrong. Nautical enthusiasts listed the numerous errors she made while dealing with naval history, and general historians pointed out that she was now relying on secondary sources, and not very good ones at that. Survivors include her husband of 48 years, Dr. Lester R. Tuchman in Cos Cob; three daughters, Lucy Tuchman Eisenberg of Los Angeles, Jessica T. Mathews of Washington and Alma Hanna Tuchman of Cos Cob; a sister, Anne Wertheim Werner of New York City, and four grandchildren. TIMOTHY F. SULLIVAN Management Analyst Timothy F. Sullivan, 74, a former lieutenant colonel in the Army reserves, a retired management anaylst and a Springfield resident since 1961, died Feb. 5 of congestive heart failure at Alexandria Hospital. Mr. Sullivan was a native of Richmond. He joined the Virginia National Guard in 1932 and went on active duty with the peacetime Army in 1941. During World War II, he served in France as an infantry company commander. He left active duty as a major in 1946 and returned to the Virginia National Guard. He transfered to the Army reserves in 1953 and retired from that organization in 1964. From 1951 to 1953, Mr.`Sullivan was a regional security officer for the Office of Price Stabilization in Richmond. He was in Annapolis from 1953 to 1958 as an administrative officer and later a management analyst for the Naval Engineering Experiment Station. After three years as a management analyst at the Army Logistics Manpower Office at Fort Lee, Mr. Sullivan became a management analyst for the Army deputy chief of staff in 1961. A year later, he went to the Cameron Station in Alexandria as chief of the Survey Branch with the Defense Supply Agency. He retired in 1972. Survivors include his wife of 39 years, Margaret M. Sullivan; a daughter, Mary Elizabeth Sullivan of Oakton; a son, Timothy F. Sullivan Jr. of Cincinnati, and two sisters, Anne Hardesty of Leonia, N.J., and Sarah Elizabeth Sullivan of King George, Va. M. MAXINE DORMER Government Accountant M. Maxine Dormer, 77, a retired accountant who had worked at the Bureau of Engraving and Printing and the Public Health Service, died of a respiratory ailment Feb. 1 at Sibley Memorial Hospital. Mrs. Dormer, who lived in Bethesda, was born in Indianola, Iowa. She moved to this area in the mid-1930s and began working at the Bureau of Engraving and Printing. Around 1960, she transferred to the Public Health Service. She retired in 1970. She was a member of the Chevy Chase Presbyterian Church and the Republican National Woman's Club. Her husband, John Dormer, died in 1977. Survivors include two brothers, Howard E. Shetterly of Manomet, Mass., and Robert L. Shetterly of Hillsboro, Va., and a sister, Edna M. Reynolds of Des Moines.