As part of the continuing growth and diver sification of Language and Cognition, this special double issue focuses on the evolution of language. Although this controver sial topic has been discussed for centuries from different per spectives, it is probably safe to say that genuine progress has only begun to take place during the past 25 years or so, as increasing numbers of researcher s have star ted pooling a broad array of relevant ideas and discoveries from a tremendous range of disciplines, including, in alphabetical order, anthropology, archeology, ar tificial life, biology, cognitive science, genetics, linguistics, modeling, neuroscience, paleontology, primatology, and psychology. The rapid expansion and maturation of this field of inquiry is evident in sever al ways. Since 1990, more and more articles about the evolution of language have appeared in prominent, high-ranking journals such as Behavioral and Brain Sciences, Trends in Cognitive Sciences, Proceedings of the National Academy of Science, and Frontiers in Evolutionary Neuroscience. In addition, the publication of books on this topic has been on the rise, and there is now a whole series of impressive monogr aphs under the rubric “Oxford Studies in the Evolution of Language.” Fur thermore, beginning in 1996, the International Conference on the Evolution of Language has been held every other year to provide a public forum for the presentation and evaluation of new developments (http://www.evolang.org/).