First I was surprised at how big this book is! A person could spend a lot of time with the book and still want to pick it up again. It isn't a book to sit down and read, but one to sit down and thumb through. I find it hard to put the book down once I start looking at it. I don't think there is a significant invention or discovery that is not mentioned. The only drawback--if you consider it that--is that there is only a page or less about each invention. While the book is thorough in including all of the inventions, it has only minimal information about each one. Still, it is a very fascinating book.