At one time or another, we have all been drawn by the fascination of the seashore. For the holiday maker, the relaxing day by the sea often turns out to be a most rewarding foray among rock pools and dense canopies of seaweed; for naturalists and students, the shore is one of the most challenging habitats. Whatever our interests and expertise, one of our first objectives when faced with the diversity of plant and animal life on the shore is to name the individual specimens and we quickly learn that this can be a difficult, though rewarding, occupation. Once an organism has been identified, a number of questions naturally follow. What is its life-cycle? How does it feed and reproduce? How long does it live? The answers to such questions give an insight into the lives of the plants and animals of the shore and are one of the first steps in an understand­ ing of the complexity of the shore environment. However, the information required to answer such questions is not always easily accessible and even when it is known it is often scattered in various books and research journals making it difficult and time consuming to find. Although a variety of identification keys and guides is available, some designed for the specialist, others for the amateur, such texts generally give little, if any, information on the biology of the organisms.