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I purchased this book for my 12 year. He's taken an interest in Quantum physics. He has kept such an interest in this book I am beyond amazed. He keeps it with him with his notebook and dictionary handy. There are some words he comes across that he's not familiar with which is completely understandable. This isn't a book for a 12 year old. It truly explains the concept of time travel not as a fantasy but as what you would have to do in order to achieve such a goal.