| Elaine O'Brien |
Anita of Rancho del Mar (age 9-12) family , historical |
| Robert C. O'Brien |
Mrs. Frisby and the Rats of NIMH (age 9-12) adventure , brilliant protagonist |
| Scott O'Dell |
Sing Down the Moon (age 9-12) adventure , historical |
|
Zia (age 9-12) adventure , historical | |
|
Sarah Bishop (age 10+) war , survival , family , historical | |
|
Island of the Blue Dolphins (age 9-12) survival , adventure , historical | |
|
The Black Pearl (age 10+) nature , spooky , adventure | |
| Barbara Oconnor |
The Small Adventure of Popeye and Elvis (age 8-11) realistic , self-reliance , adventure , humor |
| Kathleen Olmstead |
Pollyanna (age 9-12) family , friendship |
| Kenneth Oppel |
Silverwing (age 9-12) in: The Silverwing Trilogy growing up , action , adventure |
|
Sunwing (age 9-12) in: The Silverwing Trilogy growing up , action , adventure | |
|
Firewing (age 9-12) in: The Silverwing Trilogy growing up , action , adventure | |
|
Darkwing (age 10+) fantasy , action , adventure | |
| Uri Orlev |
The Island on Bird Street (age 9-12) war , survival , historical |
| Wendy Orr |
Nim's Island (age 8-11) humor , friendship , adventure , nature , survival |
| Mary Pope Osborne |
Afternoon on the Amazon (age 7-10) in: Magic Tree House Series adventure , historical |
|
Blizzard of the Blue Moon (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Buffalo Before Breakfast (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Carnival at Candlelight (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Christmas in Camelot (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Civil War on Sunday (age 7-10) in: Magic Tree House Series adventure , historical | |
|
A Crazy Day with Cobras (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Dark Day in the Deep Sea (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Day of the Dragon King (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Dingoes at Dinnertime (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Dinosaurs Before Dark (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Dogs in the Dead of Night (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Dolphins at Daybreak (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Dragon of the Red Dawn (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Earthquake in the Early Morning (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Eve of the Emperor Penguin (age 7-10) in: Magic Tree House Series adventure , historical | |
|
A Ghost Tale for Christmas Time (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Ghost Town at Sundown (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Good Morning, Gorillas (age 7-10) in: Magic Tree House Series adventure , historical | |
|
A Good Night for Ghosts (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Haunted Castle on Hallows Eve (age 7-10) in: Magic Tree House Series adventure , historical | |
|
High Tide in Hawaii (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Hour of the Olympics (age 7-10) in: Magic Tree House Series adventure , historical | |
|
The Knight at Dawn (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Leprechaun in Late Winter (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Lions at Lunchtime (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Midnight on the Moon (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Monday With a Mad Genius (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Moonlight on the Magic Flute (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Mummies in the Morning (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Night of the New Magicians (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Night of the Ninjas (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Pirates Past Noon (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Polar Bears Past Bedtime (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Revolutionary War on Wednesday (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Season of the Sandstorms (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Stage Fright on a Summer Night (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Summer of the Sea Serpent (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Sunset of the Sabertooth (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Thanksgiving on Thursday (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Tigers at Twilight (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Tonight on the Titanic (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Twister on Tuesday (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Vacation Under the Volcano (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Viking Ships at Sunrise (age 7-10) in: Magic Tree House Series adventure , historical | |
|
Winter of the Ice Wizard (age 7-10) in: Magic Tree House Series adventure , historical | |
|
My Secret War: the World War II Diary of Madeline Beck, Long Island, New York, 1941 (age 8-11) in: Dear America Series war , identity , letters/journal , historical | |
|
Standing in the Light: the Captive Diary of Catherine Carey Logan, Delaware Valley, Pennsylvania, 1763 (age 8-11) in: Dear America Series war , identity , letters/journal , historical |