- Unchosen Destiny
- Uncivil Service
- Uncle Charlie Goes Swimming
- Uncle Edgar - The Android
- Uncle Edgar - United Space Force
- Unclear Skies
- Uncommon
- Uncommon Life
- Uncommon Pet Tales
- Uncompromising Honor
- Unconquerable Sun
- Uncontainable
- Uncovering Truths: Time's Tempest Lost Chapter 4
- Uncrossed Paths
- Und führet mich zu stillen Wassern
- Undead at Groom Lake
- Undead Genesis: Zombie
- Undead Island (Escape - Vol. 3)
- Undead Island (High Tide - Vol. 1)
- Undead Island: The Complete Collection
- Undead Reckoning
- Undead Tales: 15 Thrilling Zombie Stories
- Undead Worlds 2
- Undead Worlds 3
- Under
- Under a Cloven Moon: The Satanta Run
- Under a Cretaceous Sun
- Under a Veil of Gods
- Under Arctic Ice
- Under Calcutta
- Under Different Stars
- Under New Leadership
- Under Plum Lake
- Under Roswell
- Under Shadows
- Under Siege
- Under Stars
- Under Strange Suns
- Under Test
- Under the Dark
- Under the Flickering Light
- Under the Green Star
- Under the Heel of the Aether Imperium
- Under The Knife
- Under the Knife (From the Desk of Col. Garrett Ross)
- Under the Radar: A Tale of Super City
- Under the Radar: The Blake Hemlock Chronicles
- Under the Skin
- Under the Sun
- Under The Tree That Owns Itself
- Under Two Moons: Paradisi Chronicles
- Under Your Skin
- UNDERBREAK
- Undercity
- Underdog Chronicles
- Underdogs
- Underestimation
- Underground
- Underground Man
- Underground: The Day of the Sun
- Underscore_
- Undersea Fleet
- Undersea Quest
- UnderSilver
- Undertow
- Underwater World
- Underway
- Underwood n.º 5
- Underworlds
- Undisclosed (Undisclosed Trilogy, Book 1)
- Undiscovered
- Undying Love
- Une invasion sans précédent [édition intégrale revue et mise à jour]
- Une Mer De Boucliers (Tome 10 de L’anneau du Sorcier)
- Une Planète
- Une Princesse de Mars (Cycle de Mars n° 1)
- Une princesse de Mars (Le conquérant de la planète Mars)
- Une raison de vivre ou de mourir (Pas de paradis sans... l'enfer, vol. 8)
- Une ville flottante
- Une Ville flottante
- Une ville flottante – suivi d'annexes
- UnEarthed
- UnEarthly
- Unendlichkeit
- Unersättliche Verderbtheit
- Unexpected Aliens
- Unexpected Heroines
- Unexpected Rain
- Unexpected Unplanned and into the Unknown
- Unfaithful Covenant
- Unfiction
- Unfit Magazine: Vol 4
- Unfit Magazine: Vol. 1
- Unfolding The Mystery: Stranded in Time 3
- Unfit Magazine: Vol. 1
- Unfolding The Mystery: Stranded in Time 3
- Unforgettable
- Unfurl
- Ungeahnte Welten - Das All Age Fantasy Paket Sommer 2017: Drei Romane - 700 Seiten
- Unheard Of
- Unholy Birth
- Unholy Land
- Unicorn Farmhand
- Unida aos Guerreiros
- Unidentified Flying Objects: Nine Classic Sci-Fi Stories
- Unidentified Funny Objects
- Unidentified Funny Objects 2
- Unidentified Funny Objects 4
- Unidentified Funny Objects 5
- Unidentified Funny Objects 6
- Unidentified Funny Objects 7
- Unidentified Funny Objects 8
- Unification In 6066
- Uniform of a Man
- Unintended Heroes
- Unintended Matter
- Union
- Union Forever
- Unique
- Unit 6
- United
- United As One
- United Star Systems Marines
- United We Fall
- Unity
- Unité et diversité: le combat des diwallers
- Univers transcendental
- Universal Income
- Universal Language
- Universal Maintenance
- Universally Yours, The Phoenix
- Universe For Sale
- Universi
- Universi Mondi
- Universo e altre periferie
- Universo in scatola
- Universos en expansión
- Unjust Theft
- Unknown Alien Language
- Unknown Earth Volume 2