“Intelligent life on a planet comes of age when it first works out the reason for its own existence. If superior creatures from space ever visit earth, the first question they will ask, in order to assess the level of our civilization, is: 'Have they discovered evolution yet?' Living organisms had existed on earth, without ever knowing why, for over three thousand million years before the truth finally dawned on one of them. His name was Charles Darwin.”

“Intelligent life on a planet comes of age when it first works out the reason for its own existence. If superior creatures from space ever visit earth, the first question they will ask, in order to assess the level of our civilization, is: 'Have they discovered evolution yet?' Living organisms had existed on earth, without ever knowing why, for over three thousand million years before the truth finally dawned on one of them. His name was Charles Darwin.”

“Like successful Chicago gangsters, our genes have survived, in some cases for millions of years, in a highly competitive world. This entitles us to expect certain qualities in our genes. I shall argue that a predominant quality to be expected in a successful gene is ruthless selfishness.”

Dawkins argues for the selfish gene as the primary locus of evolution. To survive, genes have to have certain characteristics. Dawkins examines these characteristics throughout the book. Dawkins often utilizes similes and metaphors to help readers visualize his ideas.

“At some point a particularly remarkable molecule was formed by accident. We will call it the Replicator. It may not necessarily have been the biggest or the most complex molecule around, but it had the extraordinary property of being able to create copies of itself.” 

Dawkins describes the origins of replicators. Replicators became genes, and genes continue to evolve today in organisms. Replicators formed complex machines to protect themselves, and these machines became plants, animals, and humans. Essentially, humans contain large collections of replicators.