Book excerpt: McGhee describes the steps involved in defining the geometric parameters (theoretical morphospaces) for an organic form in order to generate a spectrum of other possible forms that have never actually appeared. The book also addresses the simulation of actual processes of morphogenesis, with the goal of attaining a more nuanced comprehension of how evolutionary processes work. The book covers theoretical morphospaces, including those for univalved, bivalved, discrete, and branching growth systems.