Biolinguistics, the study of the relation between humans' biology and the properties of the Language Faculty, is an emergent and lively field, and is central to linguistics. It gives rise to lively debates on the origin of language, and the specificity of human language in the animal kingdom as well as the biological basis of the human language capacities. This new four volume collection assembles the most important contributions to the field, exploring the foundations of the subject and language development, variation in languages and biology, and complexities in language and biology.