This book contains the proceedings of the Sixth International Symposium on Aphids, held in September 2001 at Rennes, France, and organised by the aphidologists of Inra and the Ecole Nationale Supérieure Agronomique de Rennes (Ensar). It covers most aspects of aphid researches world-wide, gathered in five sections on Biology and Ecology - Taxonomy, Systematics and Faunistics - Genetics, Population Biology and Evolutionary Ecology - Population Dynamics, Biological Control and Integrated Pest Management - Aphid-plant Relationships. The number of papers and their diversity reflect the dynamism of the world community of aphid-working scientists.