Darwin's theory of evolution by natural selection focuses on inheritance and survival without attempting to explain the forms organisms take. The first part of Form and Transformation looks critically at the conceptual structure of Darwinism and describes the limitations of the theory of evolution. The authors argue that a theory of biological form is needed to understand the structure of organisms and their transformations. The second part of the book explores such a theory by portraying organisms as developing and dynamic systems, within which gene action is understandable. The authors present a number of specific examples, including tetrapod limb formation and Drosophila development, to illustrate how these dynamic organisms produce generic forms.