f you choose not to read this and move straight on to In Homage to Darwin, we will not be offended. The story, however, of how two scientific dinosaurs came to cooperate in writing about their shared world view, gleaned from a combined total of more than 150 years of independent study of biology, needs, we feel, some explanation.Any two biologists can be relied on to arrive at different personal understandings of Charles Darwin’s magnificent legacy. However, few were as far apart as the authors of this book when they first met in the 1970s. At that time, a split was appearing in the practice of science. Traditionalists were persevering with the reduction of whole systems into their constituent parts, an approach that had led to the triumphs of the decipherment of the genetic code and the new science of genomics. A different way of thinking was combining science and new social movements. Post-normal science was beginning to accept that, for complex issues such as planetary climate change and global food security, scientists needed to practise their art where facts were uncertain, values in dispute, stakes high and decisions urgent.