Moreover, groundbreaking research on genes, and especially key families of genes such as the Homeobox genes which controlthe development of body plans, has led to radical changes in the classification of animals. In this Very Short Introduction, Peter Holland presents a cutting-edge tour of the animal kingdom, providing an authoritative summary of the modern view of animal life, its origins, and the new classificationresulting from DNA studies. Beginning with the definition of animals (not obvious in biological terms), Holland takes the reader through the revolutionary new high-level groupings of animals (phyla) based on evolutionary relationships and ancestry. Ranging from corals and sponges to nematodes, seasquirts, and vertebrates, and illuminating many key topics in zoology, this fascinating, brief overview will be of great value to all students of the life sciences as well as providing a concise summary for the interested lay reader.