This careful, elegant, scholarly translation of Roux’s The Struggle of Parts is fascinating. Roux’s insufficiently appreciated insights were more than one hundred years ahead of their time and are especially worth reading for anyone interested in the history of fundamental ideas in evolutionary biology, functional adaptation, levels of selection, and what we today call phenotypic plasticity and epigenetics.

This translation is an important and scholarly contribution to the history and philosophy of biology. The excellent introduction and afterword introduce the rich scientific context in which Roux developed his broad concept of selection as differential persistence and point to the relevance of his ideas to current, and still debated, ideas in evolutionary biology.

This translation is to be greatly welcomed. Roux was a pioneer in experimental embryology who sought to do what Kant held to be impossible: to explain the purposiveness of organisms with the aid of mechanical principles. These efforts also inspired Nietzsche in his thinking about life and wrestling with Darwinian ideas. The edition is superb and can be recommended to anyone with an interest in the study of life.

David Haig and Richard Bondi have done a great service to a number of fields. By translating Roux’s The Struggle of Parts, they have made widely available crucial ideas by a profound thinker. Roux’s discussion of how cooperation, competition, and mutual control underlie the formation of a coherent body and mind has major implications for evolutionary and developmental biology, cognitive science, bioengineering, and even artificial intelligence.