The letters that Charles Darwin wrote immediately after the publication of On the Origin of Species are not as well known as his journal written during the voyage of the Beagle or those he wrote during the long period between his return home and the book's appearance. But they deserve to be, for they shed important light on many fascinating questions. How did he react to the sensation that his revolutionary book created? What were his religious views that he so carefully refrained from explaining in public? And what kind of life did he lead, shut away in his house in the depths of Kent, apparently cut off from his scientific colleagues in London and elsewhere?

But first, why did he not attend any of the scientific debates in London in which his thoughts on evolution played such an important part? These letters certainly make the answer to that question very clear. He was, truly, a chronically sick man. The nature of his illness may or may not have had a psychosomatic component but of its reality and severity there can be no doubt. In letter after letter he refers to his daily sicknesses. A journey will cause severe vomiting; the prospect of having to speak publicly will leave him prostrate.