- *The Assassination of John F. Kennedy: The Theories and the Evidence* (New York: Lyle Stuart, 1966)
- *Hiroshima: The Decision to Drop the Bomb* (New York: Pyramid Books, 1968)
- *The Bataan Death March: A Survivor's Account* (New York: Pyramid Books, 1970)
- *The Pearl Harbor Papers: Inside the U.S. Government's Cover-Up* (New York: Dodd, Mead & Company, 1974)
- *Vietnam Diary: The Secret Diary of the U.S. Ambassador* (New York: Lyle Stuart, 1979)
- *The New York Times Guide to the Presidency* (New York: Atheneum, 1981)
- *Encyclopedia of American Presidents* (New York: Harper & Row, 1984)
- *White House Confidential: The Hidden Lives of the American Presidents* (New York: Arbor House, 1989)
- *The Great Presidential Trivia Book* (New York: Carol Publishing Group, 1991)
- *Presidential Quotations: A Sourcebook* (New York: H.W. Wilson, 1992)
- *The Presidents' Wives* (New York: HarperCollins, 1994)
- *The Kennedys: A First-Hand Account of Their Historic Years in Washington* (New York: Random House, 2001)
- *America's Presidents: A Reference Guide* (New York: Facts On File, 2004)
- *White House Kids: The Lives of America's First Families* (New York: Skyhorse Publishing, 2011)