- Under Pressure
- Under the Microscope : Earth's Tiniest Inhabitants - Soil Science for Kids Children's Earth Science...
- Under the Sea
- Under Your Feet... Soil, Sand and Everything Underground
- Understanding Coronaviruses
- Understanding Water Activity Book
- Underwater Training
- Unelmia ja hevosia, Johanna
- Unforgettable Catastrophes
- Unforgettable Natural Disasters
- Unsolved! History's Mysteries
- Unsolved! Mysterious Events
- Unsolved! Mysterious Places
- Unsung Heroes Pioneers in Science
- Up Close With Spiders
- Uranus: Planets in Our Solar System Children's Astronomy Edition
- US States And Their Capitals: Geography 2nd Grade for Kids Children's Earth Sciences Books Edition
- Usborne Official Astronaut's Handbook