This bold new book, by one of the fields leading sociolinguists, outlines the need for a new intellectual project at the heart of our discipline, emphasising the crucial role of the small face-to-face societies that have shaped most of human history in generating the outer reaches of linguistic complexity. Nicholas Evans, Professor of Linguistics, College of Asia and the Pacific, Australian National University This focussed and important work shows that degree of contact, the size of the community of speakers, and coherence within that community are all important factors in the degree to which languages become structurally simpler (losing agreement and gender for example) or more complex. This is a must-read for anyone interested in language change. Gary Miller, author of Language Change and Linguistic Theory.