The publication of The Origin of Species in 1859 was the culmination of more than 20 years of work by Charles Darwin and the ideas he presented in it would lead to a fundamental change in the way humans think about life on earth. The theory, as revolutionary as it was, did not come out of thin air, but developed within the context of the scientific and philosophical thinking of the period. To arrive at a better understanding of the current debate, this book looks at key moments in Darwin's life and at the relevant aspects of the intellectual climate.