Shubin is a paleontologist and evolutionary biologist, and the author of Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. Shubin serves as a protagonist of Your Inner Fish, and includes personal anecdotes about his research and life throughout his discussions of evolutionary biology. Shubin introduces each chapter’s subject by describing a personal encounter with the body part whose evolutionary history he will discuss. For instance, Chapter 9, the chapter on eyesight, opens with an anecdote about a rare fossilized salamander eye in a Chinese mineral shop. 

Shubin plays a more central role in the opening two chapters, in which he describes one of his most important scientific discoveries: the fossil of the ancient creature Tiktaalik. Shubin’s hunt for the Tiktaalik fossil begins in 1995, when he is searching for fossils in rock fields in Pennsylvania. Together with his colleague Ted Daeschler, Shubin hopes to discover fossils that can shed light on the evolutionary transition that allowed fish to begin walking on land, some 350 million years ago. Shubin discovers a fossilized portion of an ancient fish, which appears to show a shoulder bone inside a fin.