- The Young Voyageurs: Boy Hunters in the NorthAuthor: Mayne Reid, William HarveyReleased on Project Gutenberg: October 20, 2007
- The Young Wireless Operator—As a Fire Patrol: Or, The Story of a Young Wireless Amateur Who Made Good as a Fire PatrolAuthor: Lewis E. (Lewis Edwin) Theiss, Frank T. MerrillReleased on Project Gutenberg: July 7, 2004
- The Young Woman's GuideAuthor: William A. (William Andrus) AlcottReleased on Project Gutenberg: October 1, 2005
- The Young Woodsman; Or, Life in the Forests of CanadaAuthor: J. Macdonald (James Macdonald) OxleyReleased on Project Gutenberg: February 1, 2006
- The Younger Edda; Also called Snorre's Edda, or The Prose EddaAuthor: Snorri Sturluson, Rasmus Björn AndersonReleased on Project Gutenberg: July 31, 2006
- The Younger SetAuthor: Robert W. (Robert William) ChambersReleased on Project Gutenberg: February 1, 2005
- The Youngest Girl in the Fifth: A School StoryAuthor: Angela Brazil, Davis, Stanley [Illustrator]Released on Project Gutenberg: June 6, 2007
- The Youth of GoetheAuthor: P. Hume (Peter Hume) BrownReleased on Project Gutenberg: November 11, 2006
- The Youth of Jefferson: Or, a Chronicle of College Scrapes at Williamsburg, in Virginia, A.D. 1764Author: John Esten CookeReleased on Project Gutenberg: November 1, 2007
- The Youth of the Great ElectorAuthor: L. (Luise) Mühlbach, Mary Stuart Harrison SmithReleased on Project Gutenberg: August 26, 2004
- The Youth's Companion, Volume LII, Number 11, Thursday, March 13, 1879Author: VariousReleased on Project Gutenberg: August 5, 2007
- The Youth's CoronalAuthor: Hannah Flagg GouldReleased on Project Gutenberg: March 1, 2004
- The Youthful Wanderer: An Account of a Tour through England, France, Belgium, Holland, Germany and the Rhine, Switzerland, Italy, and Egypt, Adapted to the Wants of Young Americans Taking Their First Glimpses at the Old WorldAuthor: Heffner, George H.Released on Project Gutenberg: January 1, 2004
- The Yukon Trail: A Tale of the NorthAuthor: William MacLeod Raine, Wolfe, George Ellis [Illustrator]Released on Project Gutenberg: October 11, 2006
- The Zeit-GeistAuthor: L. (Lily) DougallReleased on Project Gutenberg: March 26, 2006
- The Zeppelin's PassengerAuthor: E. Phillips (Edward Phillips) OppenheimReleased on Project Gutenberg: October 1, 1999
- The Zincali: An Account of the Gypsies of SpainAuthor: George BorrowReleased on Project Gutenberg: June 1, 1996
- The Æneid of Virgil, Translated into English VerseAuthor: Virgil, 71 BCE-20 BCE, Maine J. P. [Commentator], Taylor, Edward Fairfax [Translator]Released on Project Gutenberg: May 28, 2006
- TheaetetusAuthor: Plato, Benjamin JowettReleased on Project Gutenberg: April 1, 1999
- Theft: A Play In Four ActsAuthor: Jack LondonReleased on Project Gutenberg: June 25, 2007
- Their CrimesAuthor: Léon Mirman, J. Esslemont AdamsReleased on Project Gutenberg: November 1, 2003
- Their Mariposa Legend: A Romance of Santa CatalinaAuthor: Charlotte B. (Charlotte Bronte) HerrReleased on Project Gutenberg: February 1, 2004
- Their PilgrimageAuthor: Charles Dudley WarnerReleased on Project Gutenberg: October 10, 2004
- Their Silver Wedding Journey — CompleteAuthor: William Dean HowellsReleased on Project Gutenberg: October 23, 2004
- Their Silver Wedding Journey — Volume 1Author: William Dean HowellsReleased on Project Gutenberg: October 23, 2004
- Their Silver Wedding Journey — Volume 2Author: William Dean HowellsReleased on Project Gutenberg: October 23, 2004
- Their Silver Wedding Journey — Volume 3Author: William Dean HowellsReleased on Project Gutenberg: October 23, 2004
- Their Wedding JourneyAuthor: William Dean HowellsReleased on Project Gutenberg: October 23, 2004
- Their YesterdaysAuthor: Harold Bell WrightReleased on Project Gutenberg: July 1, 2004
- Theism or Atheism: The Great AlternativeAuthor: Chapman CohenReleased on Project Gutenberg: May 2, 2008
- ThelmaAuthor: Marie CorelliReleased on Project Gutenberg: March 1, 2003
- Theme from Mozart's Piano Sonata in A major, K.331: Arranged for Solo GuitarAuthor: Wolfgang Amadeus Mozart, Davis, Rick [Arranger]Released on Project Gutenberg: December 31, 2005
- Then I'll Come Back to YouAuthor: Evans, Larry, -Released on Project Gutenberg: July 22, 2006
- Then Marched the BraveAuthor: Harriet T. (Harriet Theresa) Comstock, Hicks, Anna S. [Illustrator]Released on Project Gutenberg: June 30, 2005
- Theobald, the Iron-Hearted; Or, Love to EnemiesAuthor: César MalanReleased on Project Gutenberg: February 1, 2004
- Theocritus, Bion and Moschus, Rendered into English ProseAuthor: Theocritus, Bion, of Phlossa near Smyrna, Moschus, Andrew LangReleased on Project Gutenberg: December 1, 2003
- Theocritus, translated into English VerseAuthor: Theocritus, Charles Stuart CalverleyReleased on Project Gutenberg: March 1, 2004
- Theodicy: Essays on the Goodness of God, the Freedom of Man and the Origin of EvilAuthor: Leibniz, Gottfried Wilhelm, Freiherr von, Austin Farrer, Huggard, E. M. [Translator]Released on Project Gutenberg: November 24, 2005
- Theodore RooseveltAuthor: Edmund Lester PearsonReleased on Project Gutenberg: July 1, 2003
- Theodore Roosevelt and His Times: A Chronicle of the Progressive MovementAuthor: Harold HowlandReleased on Project Gutenberg: July 1, 2001
- Theodore Roosevelt: An AutobiographyAuthor: Theodore RooseveltReleased on Project Gutenberg: April 6, 2006
- Theodore Roosevelt: An Intimate BiographyAuthor: William Roscoe ThayerReleased on Project Gutenberg: November 1, 2000
- Theodoric the Goth: Barbarian Champion of CivilisationAuthor: Thomas HodgkinReleased on Project Gutenberg: December 9, 2006
- Theological Essays and Other Papers — Volume 1Author: Thomas De QuinceyReleased on Project Gutenberg: July 1, 2004
- Theological Essays and Other Papers — Volume 2Author: Thomas De QuinceyReleased on Project Gutenberg: October 1, 2004
- Theologico-Political Treatise — Part 1Author: Benedictus de Spinoza, R. H. M. (Robert Harvey Monro) ElwesReleased on Project Gutenberg: July 1, 1997
- Theologico-Political Treatise — Part 2Author: Benedictus de Spinoza, R. H. M. (Robert Harvey Monro) ElwesReleased on Project Gutenberg: July 1, 1997
- Theory of circulation by respirationAuthor: Emma WillardReleased on Project Gutenberg: August 15, 2006
- Theory of Silk Weaving: A Treatise on the Construction and Application of Weaves, and the Decomposition and Calculation of Broad and Narrow, Plain, Novelty and Jacquard Silk FabricsAuthor: Wolfensberger, ArnoldReleased on Project Gutenberg: January 5, 2005
- Theory of the Earth, With Proofs and Illustrations, Volume 1 (of 4)Author: James HuttonReleased on Project Gutenberg: July 9, 2004
- Theory of the Earth, With Proofs and Illustrations, Volume 2 (of 4)Author: James HuttonReleased on Project Gutenberg: November 27, 2004
- There & BackAuthor: George MacDonaldReleased on Project Gutenberg: September 1, 2005
- There Are Crimes and CrimesAuthor: August Strindberg, Edwin BjörkmanReleased on Project Gutenberg: January 1, 2004
- There is No Harm in DancingAuthor: W. E. (William Evander) PennReleased on Project Gutenberg: November 27, 2004
- There Is Sorrow on the SeaAuthor: Gilbert ParkerReleased on Project Gutenberg: November 18, 2004
- There was a King in EgyptAuthor: Norma LorimerReleased on Project Gutenberg: December 26, 2007
- There's Pippins and Cheese to ComeAuthor: Charles S. (Charles Stephen) BrooksReleased on Project Gutenberg: November 1, 2003
- Theresa Marchmont, or, the Maid of Honour: A TaleAuthor: Mrs. (Catherine Grace Frances) GoreReleased on Project Gutenberg: November 1, 2005
- Theresa RaquinAuthor: Émile Zola, Ernest Alfred VizetellyReleased on Project Gutenberg: April 22, 2006
- They and IAuthor: Jerome K. (Jerome Klapka) JeromeReleased on Project Gutenberg: December 1, 2000