Charles Darwin (1809-1882) was a British naturalist, best known for his work on his theory of natural selection. He wrote "On the Origin of Species by Means of Natural Selection" after 20 years work following his visit to the Galapagos Islands on the HMS Beagle. There he saw wild animals which had slightly different features on each of the islands. The most well-known of these animals are the finches, tortoises and iguanas.
This series of stamps (I'm missing the 29p value) was issued in 1982 to commemorate the centenary of his death. He has been commemorated on a number of stamp issues - in 1999, 2006, and again in 2009.
This is a post for Sunday Stamps, now hosted by Violet Sky at "See it on a Postcard!"