“The Descent of a Man” is written by -

Charles Robert Darwin, (born February 12, 1809, Shrewsbury, Shropshire, England—died April 19, 1882, Downe, Kent), English naturalist whose scientific theory of evolution by natural selection became the foundation of modern evolutionary studies.
An affable country gentleman, Darwin at first shocked religious Victorian society by suggesting that animals and humans shared a common ancestry.

His works:
- The Origin of the Species
- The Descent of Man etc.

Source: Britannica.com