Since the invention of the wheel we have striven to make great machines that would make our lives more productive and efficient, however we will almost certainly never invent a machine as efficient as the human body. Each component of the machine is given in depth attention with the same clarity and insightful touch you have come to expect from the Eyewitness books. There are over 206 bones, half of which are in the hands and feet. A total of 640 muscles contract and exert pressure, working together with our skeleton to turn power and strength into movement and precision. Our bodies are incredibly resilient machines, and conversely life is very fragile. After all, unlike any other, this machine can reproduce itself.