This paper analyzes Charles Darwin's characteristic writing behavior. Darwin was a more interesting and dedicated writer than he is commonly credited for being. This essay will reassess the importance of his writing. The surface characteristics of Darwin's prose (conventionally referred to as his "style") seem at first glance so plain and ordinary that Darwin's writing rarely interests students of style. Exceptions such as Theodore Baird in an essay entitled "Darwin and the Tangled Bank"1 and Stanley Edgar Hyman in a longer study of Darwin's writing, The Tangled Bank,2 both make a point of the current general disregard of Darwin as a writer. But Darwin took considerable pains with the writing, particularly with his organization, sentence structure and metaphors. In his autobiography he says: "I have as much difficulty as ever in expressing myself clearly and concisely; and this difficulty has caused me a very great loss of time; but it has had the compensating advantage of forcing me to think long and intently about every sentence.... I will add that with my large books I spend a good deal of time over the general arrangement of the matter."3 And Francis Darwin in describing his father's characteristic writing behavior tells us: "On the whole, I think the pains which my father took over the literary part of the work was very remarkable" (I, 131). My analysis of Darwin’s writing will redefine style as a kind of literary ethogram of an individual’s writing behavior rigorous enough to allow a professional writer to duplicate from the analysis, using different subject matter, that same style without necessarily having seen the original text.