What is the nature of life? In this lecture I will review the revolution in biological thinking that has dramatically changed how we view life. I will review such persistent ancient ideas as spontaneous generation and why it took so long to disprove this notion, the impact of the microscope on biology, and the discovery of the laws and agency of heredity. This is obviously a highly-selective view of a vast topic, and my goal is to highlight those episodes in the history of biology that inform us about the nature of science (its successes and failures), and which we will concern ourselves with in the rest of the course. Listeners will note that I do not introduce Evolution (more precisely, Natural Selection) since that is a huge other topic for another day. Recorded live on 2009 Oct 1 in Room 1005 Smith Laboratory on the Columbus campus of The Ohio State University.