The assassin's bullet misses, the Archduke's carriage moves forward, and a catastrophic war is avoided. So too with the history of life. Re-run the tape of life, as Stephen J. Gould claimed, and the outcome must be entirely different: an alien world, without humans and maybe not even intelligence. The history of life is littered with accidents and any twist or turn may lead to a completely different world. Now this view is challenged in Simon Conway Morris' exploration of the evidence demonstrating life's almost eerie ability to repeatedly navigate towards a single solution. Are all evolutionary inevitabilities limited to the suitability of a planet? Where are our counterparts across the galaxy? If the tape of life can only run on a suitable planet, it seems that such Earth-like planets are much rarer than hoped, and we remain inevitably humans in a lonely Universe. Simon Conway Morris is the Ad Hominen Professor in the Earth Science Department at the University of Cambridge. Morris is also a fellow of St. John's College and the Royal Society. His research focuses on the study of the constraints on evolution, and the historical processes that lead to the emergence of complexity, especially with respect to the construction of the major animal body plans in the Cambrian explosion. His work is central to palaeobiology, but is also of great interest to molecular biologists and bioastronomers. Previous published works include The Crucible of Creation: Burgess Shale and the Rise of Animals (Getty Center for Education in the Arts, 1999); and co-author of Solnhofen (Cambridge, 1990).