This video-based course probes the question “Are we alone?” Unlike SETI scientists, Mars rovers and planet-hunting astronomers, we take a biological approach and ask: “How did WE get here?” Like salmon swimming upriver to the pond where they were born, we are led upstream from whence we came. We take a pilgrimage into the past to the origin of life 4 billion years ago. During this evolutionary odyssey with astrobiologist Charley Lineweaver, we ask: Who is “we”? Why did our brains get so big? How did life get started? Are viruses alive? What is life? Answers to these questions may help us get from How DID life start? to How DOES life start?