From the human being to the octopus, the shark to the humble sea squirt, all animals are physical beings made up entirely of cells. And yet all of them can think. How did this come to be? How did a mind first grow from the matter that is the body? And at what stage did that clump of cells begin to 'think'? Peter Godfrey-Smith looks beyond the octopus to the complexity of the whole animal kingdom, exploring the origins of consciousness and grappling with the greatest mystery of evolution. Metazoa (the biological term encompassing all animals), covers, with various degrees of detail, the main stages in animal evolution: the long period of life before animals, the enigmatic period known as the Ediacaran, in which the first animal fossils were laid down, then the Cambrian, the period that rapidly gave rise to most of the familiar animal forms. Then, in a few distinct evolutionary lines, the appearance of bodies with a set of unusual capacities: bodies with eyes and other senses that can track objects in space, bodies that can freely move and bodies with tools for the manipulation of objects. And the bringing together of these capacities would have pivotal consequences for the evolution of the brain and hence the evolution of consciousness. There is much to marvel at in the natural world. But take a moment to wonder at the fact that we can marvel at all.