Leonard S. Baker, 54, a former newspaperman who won the Pulitzer Prize for biography in 1979 for his book "Days of Sorrow and Pain: Leo Baeck and the Berlin Jews," died of cancer Nov. 23 at George Washington University Hospital. He lived in Washington.

Mr. Baker was born in Pittsburgh and graduated from the University of Pittsburgh. He earned a master's degree in journalism from Columbia University. He served in the Army in this country during the conflict in Korea.

He was a reporter with the St. Louis Globe Democrat before joining Newsday in New York in 1957. He transferred to the Newsday bureau in Washington in 1958. He left the newspaper in 1965 to write books.

"While I was doing the biography of Chief Justice of the United States John Marshall I got interested in the law as an institution and how society depends on it to hold itself together," Mr. Baker said in a 1979 article in The Washington Post.

"I knew about Baeck," he said, "and I began to wonder what happens to a law-abiding group like the German Jews when they're suddenly denied the protection of the law."

After five years of research and 100 interviews in 10 countries, Mr. Baker wrote the prize-winning biography of Leo Baeck, the leading rabbi of Berlin who saved thousands of Jews from the Holocaust and led them at the camp-ghetto of Theresienstadt.

Mr. Baker's other books include "The Johnson Eclipse," a study of the vice presidency of Lyndon Baines Johnson, and "Brandeis and Frankfurter: A Dual Biography."

He was a member of Temple Micah Congregation in Washington, where he was a founder of the Hebrew school.

Survivors include his wife, Liva, a son, David, and a daughter, Sara, all of Washington; his father, Charles, of Hallandale, Fla., and a brother, Sidney, of Pittsburgh.