For many people, the first experience of marine environments is amazement at the bewildering variety of life in the oceans. Sea anemones and corals, sea stars and sea urchins, octopuses and squids are just a few marine creatures that we never encounter on land or in freshwater. Many other creatures are even less familiar, and it is often difficult for those interested in marine life to learn more about them. The aim of this introductory book is to introduce the diversity of life in the seas and to help newcomers to marine biology recognise the main kinds of marine organisms. The examples selected, focus on Victoria and southern Australia. The emphasis is on animals and plants that are commonly seen by divers, snorkellers, beachcombers, rock poolingers, and by anyone with an interest in marine life.