On the Origin of Species and its ability to explain a wide range of observations. The "Examiner" review of 3 December 1859 commented, "Much of Mr. Darwin's volume is what ordinary readers would call 'tough reading;' that is, writing which to comprehend requires concentrated attention and some preparation for the task. All, however, is by no means of this description, and many parts of the book abound in information, easy to comprehend and both instructive and entertaining." While the book was readable enough to sell, its dryness ensured that it was seen as aimed at specialist scientists and could not be dismissed as mere journalism
On the Origin of Species sentence [Light will be thrown on the origin of man and his history] I show that I believe man is in same predicament with other animals. Many modern writers have seen this sentence as Darwin’s only reference to humans in the book; Janet Browne describes it as his only discussion there of human origins, while noting that the book makes other references to humanity. Some other statements in the book are quietly effective at pointing out the implication that humans are simply another species, evolving through the same processes and principles affecting other organisms. For example, in Chapter III: "Struggle