Summary

In “We Used to Be Wild,” Harari describes that millions of years ago, humans were just another animal. They differentiated themselves from the common animals when they began using tools.

In “Cooks Have Big Brains,” ancient humans also learned how to create fire and how to use fire to cook food. This allowed them to spend less energy eating and digesting food and allowed their brains to grow larger. At this point, however, humans were still considered to be just another animal. They had not yet come to rule the world.

In “Different Kinds of Humans,” Harari writes that all modern humans are technically the same even though they have different skin tones. There was a time when humans were very different, but something happened to kill off all the other types of humans except for one.

In “An Island of...