At the Water's Edge takes you to the icy peaks of Greenland, the ancient shores of the Tethys Sea, and the warm waters of the Bahamas to visit with dolphins as it surveys how we have come to understand two special cases of macroevolution. In the first, around 360 million years ago, the descendants of one lineage of fish came ashore and rushed over the continents, eventually evolving into everything from turtles and dinosaurs to elephants and people.

Then around 50 million years ago, and just as remarkably, one branch of these descendants crept back into the water and evolved into whales, dolphins, and other highly intelligent underwater life. The resulting portrait of the origin of whales is as marvelous as it is compelling. The story begins before Darwin's revolution when the first mysterious fossils from these transitions were unearthed - often by colorful entrepreneurs more familiar with the techniques of the circus than those of the laboratory.

Escorting us along the trail of discovery up to the current dramatic research in paleontology, ecology, genetics, and embryology, Zimmer shows how scientists today are unveiling the secrets of life that biologists struggled with two centuries ago.