The Selfish Gene is a book on evolution by Richard Dawkins, published in 1976. It builds upon the principal theory of George C. Williams's first book Adaptation and Natural Selection. Dawkins used the term "selfish gene" as a way of expressing the gene-centered view of evolution as opposed to the views focused on the organism and the group, popularizing ideas developed during the 1960s by W. D. Hamilton and others. From the gene-centered view follows that the more two individuals are genetically related, the more sense (at the level of the genes) it makes for them to behave selflessly with each other. This should not be confused with misuse of the term along the lines of a selfishness gene.