Why life might be widespread in the universe -- Habitable zones of the universe -- Building a habitable Earth -- Life's first appearance on Earth -- How to build animals -- Snowball Earth -- The enigma of the Cambrian explosion -- Mass extinctions and the Rare Earth Hypothesis -- The surprising importance of plate tectonics -- The Moon, Jupiter, and life on Earth -- Testing the Rare Earth Hypotheses -- Assessing the odds -- Messengers from the stars
