"Why? How come? Fun! The Wonders of Science for 1st Graders" Price: ¥800 "Why? How come? Fun! The Wonders of Science for 2nd Graders" Price: ¥800 "Why? How come? Fun! The Wonders of Science for 3rd Graders" Price: ¥850 "The Wonders of the Heart: Why? How come?" Price: ¥850 Tetsuya Murayama / Masato Ohno Set of 4 books. Both my child and I enjoyed these books!"