Darwin's Bluff

Tucked away in Charles Darwin's surviving papers is a manuscript of almost 300,000 words that he never completed. It was his sequel to The Origin of Species. It was the book he had promised would finally supply solid empirical evidence for the creative power of natural selection, evidence he admitted was absent from the Origin, which he repeatedly described as a "mere abstract." Darwin soon abandoned his sequel, though he never revealed that decision to those who awaited its appearance. The...