Who wrote 'Essay on the Principles of Evolution'?

Answer 1

Perhaps you mean the Principles of Population by Thomas Malthus?

Otherwise, perhaps your question may be referring to some work by Charles Darwin.

Answer 2

Alfred Russel Wallace and Charles Darwin independently developed the theory of evolution by natural selection. Wallace's paper on the subject, titled "On the Tendency of Varieties to Depart Indefinitely from the Original Type," was presented jointly with Darwin's work to the Linnean Society in 1858. Darwin later expanded on his ideas in the book "On the Origin of Species."