My wife bought this for our 6 year old when he was 3 and he loved it. She also bought a bunch of the other science books for babies. He insisted that I read "general relativity for babies" multiple times every night for months. He loved that I used a bendable surface to demonstrate warping space with mass. I was actually blown away that he was understanding the concepts, which I credit the books for. Adults love these books, too. Hell, for what it's worth I have a science degree and I love these books. YouTube has videos of the author reading each book if you want to preview them. I thought they were going to be a gimmick and useless, but I recommend checking them out.