Olson, Karen E.
- Information about the author of Sacred Cows, which features police reporter Annie Seymour.
- http://www.kareneolson.com/

O'Shaughnessy, Perri
- Author(s) of the Nina Reilly legal mysteries.
- http://www.perrio.com/

Orrell, David
- Author of Gaia, an eco-thriller set in Latin America. Includes a synopsis, excerpt, and information about the Gaia Theory.
- http://www.gaianet.fsbusiness.co.uk/