We owe our understanding of the world around us to the insights and experiments of countless scientists. This volume introduces just over one hundred of the most influential figures in the history of the field. It spans thousands of years, from Thales of Miletus (who flourished in the sixth century BCE) to living luminaries, such as Craig Mello, Neil deGrasse Tyson, and Shinya Yamanaka. The varied and fascinating list includes physicists, chemists, anthropologists, astronomers, geologists, biologists, and more, all of whom have added to our store of scientific knowledge.