Mary Margaret Truman Daniel (born February 17, 1924) is an American writer and the author of biographies, books on the White House and several best-selling mystery novels.

She married New York Times reporter, and later editor, Clifton Daniel (1912-2000) on April 21, 1956, at the Trinity Episcopal Church in Independence, MO. Their sons are: Clifton Truman Daniel (born 1957), William Wallace Daniel (1959-2000), who was killed in a taxi cab collision in New York City, Harrison Gates (born 1963), and Thomas Washington Daniel (born 1966).

Daniel is the daughter of 33rd president Harry S. Truman and his wife, Bess Truman. She was christened Mary Margaret Truman. Mary, for her aunt, Mary Jane Truman, and Margaret, for her maternal grandmother, Margaret Gates Wallace.

In the 1940s, Daniel aspired to be a singer. After graduating from George Washington University and undergoing some classical vocal training, she debuted in a vocal recital on the radio in March 1947. Music critic Paul Hume gave that recital an unfavorable review, resulting in an incident in which President Truman threatened to punch the reviewer in the nose. Despite the bad press, Daniel performed on the stage, radio and television well into the 1950s.

In 1944, she christened the battleship USS Missouri (BB-63), named for her home state. When the ship was recommissioned in 1991, she was a featured speaker at the ceremony.

Shortly before her father's death in 1972, Daniel, under her maiden name published Harry S. Truman, a full length biography of her father, which was critically acclaimed. The book extensively used sources from Presidential papers in the Truman Library. Daniel followed this book with a volume of her mother's life, Bess Truman, which covered the life of the Truman's from an insider's perspective as opposed to a macro-view perspective taken in Harry S. Truman.

Daniel also authored books on White House first ladies and pets.

After the death of her son in 2000, Daniel sued a taxi cab company in New York City and won a considerable sum of money.

She is now 81 years old, and continues to reside in New York.

Bibliography

• Murder in the White House - 1980
• Murder on Capitol Hill - 1981
• Murder in the Supreme Court - 1982
• Murder in the Smithsonian - 1983
• Murder on Embassy Row - 1984
• Murder at the FBI - 1985
• Murder in Georgetown - 1986
• Murder in the CIA - 1987
• Murder at the Kennedy Center - 1989
• Murder at the National Cathedral - 1990
• Murder at the Pentagon - 1992
• Murder on the Potomac - 1994
• Murder at the National Gallery - 1996
• Murder in the House - 1997
• Murder at the Watergate - 1998
• Murder in the Library of Congress - 1999
• Murder at Foggy Bottom - 2000
• Murder at Union Station- 2004