The shape of our hands, the way our heads are organized, the reason we hiccup—all and more can be traced back to prehistoric fish, says Neil Shubin, associate dean for organismal and evolutionary biology at The University of Chicago, in his new book, Your Inner Fish. Shubin traces the evolutionary history of our bodies (genes and bones) and our social behaviors back hundreds of millions of years to our ancestors of the sea, including Tiktaalik, the half-fish, half-amphibian creature—a "missing link" between fish and land animals—that he helped discover in the Canadian Arctic in 2004. "We humans are first and foremost primates," concludes Barbara King, a professor of biological anthropology at the College of William and Mary, in her review of the book. "Nevertheless, Shubin is dead right: The elegance and full emotional power of our connection with the natural world compel us to reach further back in time and deeper into the Earth's fossil layers." —Heather Wax