One Door Away from Heaven
Dean R. Koontz
Once a Wolf
Susan Krinard
Val Cache (4)
On the Trail of the Space Pirates
Carey Rockwell
Tom Corbett Space Cadet (3)
On the Surface
Robert J. Sawyer
H. G. Wells' Time Machine Universe (1)
On the Oceans of Eternity
S. M. Stirling
Nantucket (3)
On the Beach
Nevil Shute
On Basilisk Station
David Weber
Honor Harrington (1)
On a Pale Horse
Piers Anthony
Incarnations of Immortality (1)
The Omicron Invasion
Edward E. Smith & Stephen Goldin
Family D'Alembert (9)
Old Tin Sorrows
Glen Cook
Garrett, P. I. (4)
Ogre, Ogre
Xanth (5)
Odyssey
Homer
October's Baby
Dread Empire (4)
Ocean Under the Ice
Robert L. Forward & Martha Dodson Forward
Rocheworld (4)
An Occurrence at Owl Creek Bridge
Ambrose Bierce
Obsidian Butterfly
Laurell K. Hamilton
Anita Blake (9)
The Oathbound Wizard
Christopher Stasheff
A Wizard in Rhyme (2)
Oath of Fealty
Larry Niven & Jerry Pournelle
The Number of the Beast
Robert A. Heinlein
Lazarus Long (1)
Now Wait for Last Year
Philip K. Dick