How does a single cell develop into myriad different specialised cell types, control the organization of these different cells into tissues and organs, and ultimately form an unimaginably complex living organism such as a human? Furthermore, how is it possible for some adult animals, but not others, to regenerate fully functioning limbs? Principles of Development opens up the fascinating field of developmental biology to those wanting to understand the answers to questions such as these. Cutting edge science is explained clearly and succinctly and is richly illustrated with a variety of custom drawn figures, animations, and links to online movies that show development happening in real time. The emphasis throughout the text is always on the key principles of development - the underlying processes shared by diverse groups of organisms. This focus on principles provides a framework on which a richer understanding of specific topics can be built. Moreover, extensive pedagogical support is provided, both in the book and online, making this text the complete package for those studying developmental biology.