[Book Overview] This set includes picture books on the theme of science and questions for children. It features "Kagaku Naze Doushite" for 1st graders and "Naze? Doushite?" for 3rd and 4th graders, with content tailored to each age group. [Publisher Information] Both books are published by Kaiseisha, known for their reliable and educational content. ISBN information is also provided for accurate purchasing and searching. [Size and Thickness] The "Kagaku Naze Doushite" on the left is approximately 2cm thick, and the "Naze? Doushite?" on the right is approximately 1cm thick. They are sized for easy handling and readability by children. - Book Title: Kagaku Naze Doushite 1st Grade - Book Title: Naze? Doushite? 3rd & 4th Grade - Publisher: Kaiseisha The spines have slight sun fading, but the insides are in clean condition.