In June 2004, science historian Frank Sulloway and the author (Michael Shermer) spent a month retracing Charles Darwin's footsteps in the Galápagos Islands.

Shermer, who was in very good physical condition, found this a very challenging excursion due to a lack of water and a harsh environment.

In a journal entry 9 months later, Darwin refers to the different mockingbirds he collected on the Galápagos Islands as "varieties" rather than an evolution of separate species.

He took a course in evolution to see the other side of the debate, and quickly realized that creationist literature "presented a Darwinian cardboard cutout that a child could knock down."

When a small group of one species breaks away and becomes geographically isolated it can experience rapid genetic changes that happen too quickly to produce a significant fossil record.

Niles Eldridge and Stephen Jay Gould apply this to the fossil record and suggest that changes occur in this approximately discontinuous manner, which they call "punctuated equilibrium."

William Whewell, a nineteenth century philosopher, suggested that to prove a theory one needs a "convergence of evidence" from different paths.

In addition to the convergence of evidence from different branches of science, a comparative method is used to examine how characteristics evolve together across species when adapting to changing environmental or other conditions.

Humans have numerous useless vestigial structures including: male nipples, male uterus remnant, thirteenth rib (in some humans), coccyx (tail bone), wisdom teeth, appendix, body hair, goose bumps, extrinsic ear muscles, and third eyelid remnant.

Shermer gives an example where the method was used by Jack Horner (paleontologist) to explain the mystery of what had happened to a large herd of Maiasaurs whose fossil remains all shared some unusual characteristics: the bones were aligned, separated by size, and fractured lengthwise.

In 1925 William Jennings Bryan prepared a speech to make at the famous "Scopes Monkey Trial" related to the teaching of evolution.

Shermer gives several reasons to engage in debate with intelligent design advocates: Scottish philosopher David Hume once stated an important maxim: “no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact, which it endeavors to establish.” This is often stated as "extraordinary claims require extraordinary evidence."

Darwin has provided fairly extraordinary evidence in favor of evolution, creationists have not done so for their claim of supernatural creation and the burden of proof lies with them.

The prosecution was able to show quite easily that this was just a reinvented version of creation-science which had been previously ruled unscientific by the Supreme Court and was therefore not allowed to be presented as an alternative scientific theory in the classroom.

Shermer describes his friendly interactions with William Dembski, Paul Nelson, and Stephen C. Meyer who are proponents of intelligent design.

Phillip E. Johnson, fountainhead of the intelligent design movement and author of "The Wedge of Truth," put it very bluntly: "This is not just an attack on naturalism, it's a religious war against all of science."

At a meeting of the Bible Institute of Los Angeles, Paul Nelson acknowledged "Easily the biggest challenge facing the ID community is to develop a full-fledged theory of biological design."

Lee Anne Chaney, a professor of biology and a Christian says: "I don't think intelligent design is very helpful because it does not provide things that are refutable."

Organizations promoting intelligent design are heavily funded by right wing religious groups, some of whom think this should be a Christian nation rather than a secular one.

Darwin, in the 2nd edition of "On the Origin of Species," stated that he saw no reason for the theory of evolution to be considered incompatible with religious beliefs.

Shermer estimates that 96 million American Christians believe that God used evolution to guide the process of creating advanced forms of life.

Shermer points out that many other scientific facts have a much wider acceptance, including the sun-centered solar system, gravity, continental drift, the germ theory of disease, the genetic basis of heredity, etc.

Shermer proposes that there is a similarity between Darwin's theory of natural selection and Adam Smith's concept of the "invisible hand" in free market economics.

Shermer mentions his long time desire to visit there after reading about it in an autobiographical book by physicist Richard Feynman called "Surely You're Joking, Mr.

In order to demonstrate the logical absurdity of intelligent design, Shermer closes out the book with an amusing rewriting of Genesis as a scientific document.

Christopher Hitchens commented on the book, "With his forensic and polemical skill, he could have left them for dead: instead he generously urges them to stop wasting their time (and ours) and do some real work.

Anyone who has been snowed into thinking that there is a real scientific controversy over evolution by natural selection will be enlightened by Why Darwin Matters, which is both genial and intellectually uncompromising.

"[1] Norman Levitt states that the book "gets high marks for its amiable style, its readability, and the unmistakable moral passion of the author.

[2] Tania Lombrozo states "Shermer’s own experiences and expertise make him uniquely suited to the task of explaining the overwhelming evidence for evolution...and why it is under attack."

"[3] Jim Walker wrote, "This book should appeal to Christians who want to understand evolution but who do not want to feel offended by the anti-religious tone of some evolutionary scientists.