How did the advent of refrigeration help create the golden age of Hollywood? How did the invention of flash photography help shift public opinion on the plight of New York's poorest inhabitants and bring about social reform? And what about our battle against dirt? How did that help create the microchips in our smartphones and computers? In How We Got to Now, Steven Johnson traces six essential innovations that made the modern world; from their origins in ancient history to the technological advancements of recent years.