This study of the sedimentary activity of trace-making animals is intended as a course book for advanced students rather than a general introduction to ichnology. Unlike most books on the subject which start with a geological approach, this book starts with the organisms that create the structures that become trace fossils. The text is arranged in two parts, beginning with an examination of animal-substrate relationships in a broad spectrum of different organisms and behavioural programmes. On the basis of this neoichnological approach, the second part then takes a new look at palaeoichnology and applies biological principles to trace fossils and biogenic textures as found in sedimentary rocks.