=Optic, O. [W. T. Adams.]= _Young America abroad series_:-- 6. Down the Rhine. 7. Up the Baltic. 8. Northern lands. 9. Cross and Crescent. 10. Sunny shores. 11. Vine and olive. 12. Isles of the sea.
=Orczy, Baroness.= _Romances of the French Revolution_:-- 1. The Scarlet Pimpernel. 2. I will repay. 3. The elusive Pimpernel. 4. The League of the Scarlet Pimpernel. 5. Eldorado. 6. Lord Tony’s wife. 7. The Scarlet Company. _Dutch War of Independence series_:-- 1. Leatherface. 2. Flower o’ the Lily. 3. The laughing cavalier. 4. The first Sir Percy.
=O’Riordan, C.= 1. Adam of Dublin. 2. Adam and Caroline.
=Osgood, M. A.= 1. Little Canary’s daisy. 2. Little Canary. 3. Little Canary’s Cousin Eugene. 4. Little Canary’s black cats.
=Ostrander, I.= _McCarty series_:-- 1. The clue in the air. 2. The twenty-six cases. 3. How many cards?
=Otis, J. [J. O. Kaler.]= _Boy scout series_:-- 1. Boy scouts in the Maine woods. 2. Boy scouts in a lumber camp. _Boys venture series_:-- 1. The Sarah Jane: Dicky Dalton, captain. 2. The cruise of the Phœbe. _Navy boys series_:-- 1. With Grant at Vicksburgh. 2. With Sherman to the sea. _Pioneer series_:-- 1. Peter of New Amsterdam. 2. Calvert of Maryland. 3. Stephen of Philadelphia. 4. Hannah of Kentucky. 5. Benjamin of Ohio. 6. Martha of California.
=Otis, J. [J. O. Kaler.]= _Pioneer series (continued)_:-- 7. Seth of Colorado. 8. Antoine of Oregon. 9. Philip of Texas. _Silver Fox Farm series_:-- 1. The wireless station at Silver Fox Farm. 2. The aeroplane at Silver Fox Farm. 3. Building an airship at Silver Fox Farm. 4. Airship cruising from Silver Fox Farm. _Stories of American history_:-- 1. Defending the island. 2. How we destroyed the Gaspee. 3. Boston boys of 1775. 4. When Dewey came to Manila. 5. Off Santiago with Sampson. 6. When Israel Putnam served the king. 7. The signal boys of ’75. 8. Under the liberty tree. 9. The boys of 1745 at the capture of Louisberg. 10. An island refuge: Casco Bay in 1676. 11. Neal, the miller. 12. Ezra Jordan’s escape. _Stories of newsboy life_:-- 1. Jenny Wren’s boarding-house. 2. The boys’ revolt. 3. Jerry’s family. 4. Teddy and Carrots. 5. The princess and Joe Potter. 6. Larry Hudson’s ambition. _Toby Tyler series_:-- 1. Toby Tyler. 2. Mr. Stubbs’s brother.