Rare Earth proposes that Complex life is rare in the Universe. Paradoxically it first points out how abundant simple life is on Earth, in deep ocean vents, several km below the Earths surface, geysers: places that a few decades ago we would have considered completely inhospitable turn out to host life. But, they argue, complex animal and plant life (eucaryotic life) takes special conditions that they argue are probably unique.

This book is an excellent starting location for someone learning about the state of the art in astrobiology. It summarises well the myriad sciences involved in why life exists on Earth, from astrophysics (is our place in the Galaxy special), planetary development (why only Earth appears to have life in our Solar system), through aspects of geology and biology that we begin to understand. I well recommend this book to anyone interested in these fields. It also has a sufficient reference section to continue the discussion.