Recent research in biomechanics is increasingly revealing a set of special cases where universal physical laws constrain the trajectories and, more controversially, even the endpoints of the evolutionary process. For the first time this book brings together a broad range of examples from the latest research in evolutionary biomechanics to examine this phenomenon. Each chapter follows a similar theme, dealing first with the underlying physics and then examining the biological responses to selection. Examples of convergent evolution are used to analyze the nature of the trajectories of adaptation during the progressive approach towards a physically defined optimum. This advanced textbook is suitable for graduate level students as well as professional researchers in the fields of biomechanics, physiology, evolutionary biology and palaeontology. It will also be of relevance and use to researchers in the physical sciences and engineering.