| Robert C. O'Brien |
Mrs. Frisby and the Rats of NIMH (age 9-12) adventure , brilliant protagonist |
| Barbara O'Connor |
How to Steal a Dog (age 8-11) growing up , family , enterprise |
| Scott O'Dell |
Sing Down the Moon (age 9-12) adventure , historical |
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Zia (age 9-12) adventure , historical | |
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Island of the Blue Dolphins (age 9-12) survival , adventure , historical | |
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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 |
| Kenneth Oppel |
Silverwing (age 9-12) in: The Silverwing Trilogy growing up , action , adventure |
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Sunwing (age 9-12) in: The Silverwing Trilogy growing up , action , adventure | |
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Firewing (age 9-12) in: The Silverwing Trilogy growing up , action , adventure | |
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Darkwing (age 10+) fantasy , action , adventure | |
| Uri Orlev |
The Island on Bird Street (age 9-12) war , survival , historical |
| Mary Pope Osborne |
Christmas in Camelot (age 7-10) in: Magic Tree House Series adventure , historical |
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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 | |
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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 | |
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My Brother's Keeper: Virginia's Civil War Diary (age 7-10) in: My America Series letters/journal , historical |