First Published in 1997. The papers in this volume on invertebrate behaviour, predominantly ant behaviour, are presented as a tribute to T. C. Schneirla and to his theoretical and experimental contributions to our understanding of the development and evolution of behaviour. His emphasis on development also brought to the fore new questions, many of which are addressed in this volume. Advances in technical instrumentation for research will be useful in reformulating these old questions in new and significantly constructive programs for responsible research. The theoretical contributions of Schneirla will continue to prove an important facilitation of those new research techniques.