We don't think much about nails and screws, until we need to fix or build something. The screw is a fundamental tool in nearly all construction projects. While it may be small, it is a powerful invention that has changed the world forever. This accessible book introduces readers to this simple machine and its many uses through real-world examples. Detailed pictures with thorough annotations help readers understand key engineering concepts. Fascinating "Technology in Action" spreads give readers an inside look at how screws work. A fun spin on essential engineering information, this accessible book will have a place in any science curriculum.