After six years scouring the Canadian Arctic with several colleagues, native Philadelphian, paleontologist, and professor of anatomy Neil Shubin discovered a 375-million-year-old fossil representing a “missing link” between ancient sea creatures and the first animals to walk on land-a fish that could do a “version of a pushup,” he says. Shubin’s book Your Inner Fish takes readers on an organ-by-organ journey through the human body to explain why we look the way we do.