Authors O
- O'Higgins, Harvey
- O'Brien, David Wright
- O'BRIEN, Fitz-James
- O'BRIEN, Howard Vincent
- OATES, Joyce Carol
- OBST, Peter J.
- ODELL, Rae
- O'DONNELL, Elliott
- OGBURN, Dorothy
- OGILVIE, Maud
- OGLESBY, Joseph Woodson
- O'HAGAN, John
- OHIO ARCHAEOLOGICAL AND HISTORICAL SOCIETY
- OLCOTT, Frances Jenkins
- OLD SLEUTH
- OLIPHANT, Laurence
- OLIPHANT, Margaret
- OLIPHANT, Mrs.
- OLIVER, Vere Langford
- OLLIVANT, Alfred
- OLSEN, Lance
- O'NEILL, Eugene
- O'NEILL, Rose Cecil
- ONIONS, Oliver
- OPPENHEIM, E. Phillips
- OPTIC, Oliver (William Taylor Adams)
- ORCZY, Baroness
- O'REILLY, John Boyle
- O'RELL, Max
- O'ROURKE, Frank
- O'ROURKE, Monica
- ORR, Charles E.
- ORR, Lyndon
- ORTON, Louise Fuller
- ORVIETO, Laura
- ORZESZKO, Eliza
- OSBORNE, Tom
- OSBORNE, William Hamilton
- OSBOURNE, Duffield
- OSBOURNE, Lloyd
- OSTROVSKY, Alexander
- OSTROVSKY, Nicholas
- OUIDA
- OURSLER, Will
- OVERTON, Grant
- OWEN, Dean
- OWEN, Hans C.
- OXENHAM, John