Alfred Russel Wallace (1823–1913) is regarded as the co-discoverer with Darwin of the theory of evolution. It was an essay which Wallace sent in 1858 to Darwin (whom he greatly admired and to whom he dedicated his most famous book, The Malay Archipelago) which impelled Darwin to publish an article on his own long-pondered theory simultaneously with that of Wallace. As a travelling naturalist and collector in the Far East and South America, Wallace already inclined towards the Lamarckian theory of transmutation of species, and his own researches convinced him of the reality of evolution. On the publication of On the Origin of Species, Wallace became one of its most prominent advocates, and Darwinism, published in 1889, supports the theory and counters many of the arguments put forward by scientists and others who opposed it.