Almost everyone has heard of this book. But, how many people have actually read it? If you havent yet, it is well-worth reading. Darwin spent over 20 years researching his ideas, preparing his arguments, and writing this book. He did a great job! On the Origin is surprisingly easy to understand. Just look at the beginning. Instead of trying to leap directly into his basic idea and premise, Darwin chooses to gradually lead the reader up to the basic idea of evolution by first point out how humans have caused evolution to occur in our domesticated animals (something very easy for all humans to see even in the 1850s). Darwin then goes on to point out some of the evidence that he and others had seen at that time that indicated that evolution had occurred. His leap in understanding the basic premise of evolution is amazing especially when you consider that he did not understand or have access to information about the basics of genetic passing of traits within species. For such a landmark publication that is the basis of modern biology, its surprisingly readable and very accessible to the non-specialist.