Charles Darwin initially sketched out his ideas about evolution by natural selection in 1842; however, he didn't actually publish a full book, detailing his ideas, until:

1859.

Explanation:

Charles Robert Darwin was a biologist, geologist and naturalist who gave the theory of evolution. He first came with his ideas of natural selection in the year 1842 however, he published a full book with all the necessary details after 16 years in the year 1859. The book was named as "On the Origin of Species" and it is considered to be the basis of the evolutionary biology.

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