Who is that dolphin in the mirror? When a dolphin looks in a mirror, does it know it is looking at itself? Dolphin expert Diana Reiss says yes, and her colleagues agree. Reiss has spent 30 years studying dolphins and getting to know them as intimately as one can hope to know a marine mammal species. Central to her research were experiments to determine if a dolphin could recognize itself as itself in a mirror, rather than thinking it is seeing another dolphin. Mirror self-recognition is considered a sign of extremely high intelligence, and was previously believed possible only in humans and higher primates such as chimpanzees. Dolphins have now been added to that elite category. Once a dolphin figures out that the image in the mirror is himself, he will explore his body, gazing into his own eyes, checking out his teeth, and displaying various body parts for self-inspection. If a researcher makes a mark on a dolphin's body, the dolphin will quickly swim to the mirror and orient himself so as to look at the mark. This "mark test" was first used on primates and is considered the definitive proof of mirror self-recognition. The self-recognition findings are the pinnacle of Reiss's work, but there's much more to the book. She discusses dolphin myths in various cultures and the centuries-long history of man's fascination with dolphins. She also outlines some of her other dolphin intelligence studies, including an underwater keyboard dolphins could use to select a specific toy or other reward. The stories of dolphin antics during the various experiments were my favorite parts of the book. The author is careful not to ascribe human traits to these animals, but it seems to me they have quite a sense of humor. They're also prone to behaviors strongly resembling empathy and service. Near the end of the book, Reiss slips out of her role as scientist and into that of activist. She describes the brutal slaughter techniques used on dolphins in Taiji, Japan. These practices were the subject of the 2009 film "The Cove," which won an Academy Award for Best Documentary Film. These dolphins are the victims of several methods of slow, painful death, including something resembling a torture rack. The Japanese government has refused to ban these inhumane practices, but Diana Reiss is not giving up.Reiss writes with a style that is easy for anyone to understand. She maintains scientific integrity while avoiding pretentiousness or oversimplification. The organizational structure of the book seems a little odd at times, but it's not a major drawback. The stories of the antics and exploits of the dolphins Reiss worked with over the years made me laugh out loud, and sometimes laugh and cry at the same time. I would have liked to see even more of these stories, and perhaps a little less of the history of research done on species other than dolphins.