• The Greats
• The Grk Books
• The Hardy Boys
• The Healing Wars
• The Heinemann Science Scheme
• The Heir Chronicles
• The Henry Hunter Series
• The Heroes of Olympus
• The History Detective Investigates
• The Hollow Gods
• The Hundred-Mile-An-Hour Dog
• The IBM Research Symposia Series
• The Imaginary Veterinary
• The Immortals
• The Incredible Worlds of Wally McDoogle
• The Infernal Devices
• The Inheritance Cycle
• The International Cryogenics Monograph Series
• The Jolly Postman
• The Just Grace Series
• The Kane Chronicles
• The Killer Cat
• The Lady Grace Mysteries
• The Land of Stories
• The Last Descendants
• The Last Dogs
• The League of Sharks Trilogy
• The League of Unexceptional Children
• The Lebedev Physics Institute Series
• The Legend of Frog
• The Legion
• The Lemonade War Series
• The Little Reader Series
• The Lorien Legacies
• The Lost Books
• The Lunar Chronicles
• The Maeve Chronicles
• The Magician Trilogy
• The Magnolia League
• The Malichea Quest
• The Map to Everywhere
• The Mini Museum Series
• The Mole Sisters
• The Morgan Kaufmann Series in Computer Graphics
• The Movie Storybook
• The Mysteries of Maisie Hitchins
• The Mysterious Benedict Society
• The Naturals
• The Nautilus Series
• The New Mexico Experience