This field guide has been thoroughly revised and expanded. It provides detailed descriptions of around 280 species of lower animals and fish. The handy travel companion is the result of many years of observation and literature research by the author. The animal and underwater world of the Mediterranean, our "home sea," fascinates hundreds of thousands of vacationers every year. While snorkeling and diving, they encounter the diverse species and life forms of lower animals and fish, about which they wish to learn more. This led to the idea for this practical field guide covering the most common and characteristic animal species of the Mediterranean. It offers all the necessary information for the approximately 280 species described in detail, including identification features, potential confusions, habitat, lifestyle, and biology, as well as care instructions for those species that are also kept in aquariums.