Discover how the world's greatest inventions work in this funny and accessible novelty book by inventions expert, Adam Hart-Davis. If you've ever wondered why the pencil came into existence, or how a steam engine works, or when we started using flushing toilets, this book has all the answers. Based on seven key areas of invention, Adam Hart-Davis tells the stories behind steam power, lighting, toilets, clocks, communication, bikes and flight, and how they are still relevant to our world today.