Leonard Mlodinow guides us through the critical eras and events in the development of science, all of which, he demonstrates, were propelled forward by humankind's collective struggle to know. From the birth of reasoning and culture to the formation of the studies of physics, chemistry, biology, and modern-day quantum physics, we come to see that much of our progress can be attributed to simple questions - why? how? - bravely asked. Mlodinow profiles some of the great philosophers, scientists, and thinkers who explored these questions - Aristotle, Galileo, Newton, Darwin, Einstein and Lavoisier among them - and makes clear that just as science has played a key role in shaping the patterns of human thought, human subjectivity has played a key role in the evolution of science.