Names
- O'Brien, Patrick Henry, 1868-1959.1
- O'Connor, Jessie Lloyd1
- O'Connor, Jessie Lloyd, 1904-1
- Ohio Council on Alcohol Problems.1
- Olmstead, Mildred Scott1
- Olmsted, Mildred Scott, 1890-1990.1
- Overholt, Gerald.1
- Paul, Alice, 1885-1977.1
- Pauling, Linus, 1901-1
- Pauling, Linus, 1901-1994.1
- Pegler, Westbrook, 1894-1969.1
- Pelley, William Dudley, 1890-1965.1
- People's Council of America.1
- Perez-Banuet, Alicia.1
- Perkins, Jonathon Ellsworth.1
- Pike, James A. (James Albert), 1913-1969.1
- Prohibition National Committee (U.S.)1
- Prohibition National Convention (1912 : Atlantic City, N.J.)1
- Prohibition National Convention (1916 : Saint Paul, Minn.)1
- Prohibition National Convention (1920 : Lincoln, Neb.)1