Drawings and descriptions of big trucks and other heavy equipment. The final page warns that these machines "can be dangerous as well as wonderful . . . it depends on the men and women who use them. If the people who use them are quick and greedy, the big machines will destroy. If the people are patient and thoughtful, the machines will build. Heavy equipment has no mind of its own."

The concluding message is similar to my understanding of what Norbert Wiener said in God and Golem about people being ultimately responsible for the actions of the machines they create. ( )