Pulleys are part of our daily lives, from elevators to giant cranes. We wouldn't even be able to raise the flag without the powerful pulley. Readers will learn all about this important, simple machine through detailed pictures with thorough annotations. They'll explore key engineering topics and learn about real-world examples of pulleys. Cool Technology in Action spreads give readers an inside look at how pulleys work. This accessible book is the perfect introduction to this simple machine and is sure to encourage an interest in STEM.