Who are you? That question has become ever more complicated over the last decade of scientific discovery. Our genomes show signs of ancestry from Neanderthals and other extinct hominins, not to mention the genetic fossils of ancient viruses. Our bodies are home to trillions of bacteria and other microbes that sculpt our organs, train our immune systems, digest our food, and influence our minds. Our brains are made up of about 80 billion neurons in 100 trillion connections. Scientists are mapping the brain in molecular detail, but their maps are raising more questions than answers. Join science writers Carl Zimmer and Ed Yong as they chat about what it even means to be an individual in the era of modern biology, while trying not to have an existential crisis on stage.