Peter Godfrey-Smith, the scuba-diving philosopher, examined the evolution of sentience and how that consciousness shaped and was shaped by animal bodies in his previous books. Now, he takes that line of questioning a step further, asking, how has life shaped and been shaped by our planet? From cyanobacteria, through algae on to ferns or trees or grasses, and from protists through invertebrates and fish through the dinosaurs and on to birds and mammals – our planet has seen an explosion of life forms, all reacting to their environment and all creating new environments that allow other life to evolve. He visits Rwandan gorillas and Australian bowerbirds, considers the impact of language and writing, and weighs the responsibilities our unique powers bring with them, as they relate to factory farming, habitat preservation, climate change, and the use of animals in experiments.