Book excerpt: In the World Library of Educationalists series, international experts themselves compile career-long collections of what they judge to be their finest pieces – extracts from books, key articles, salient research findings, major theoretical and practical contributions – so the world can read them in a single manageable volume. Readers will be able to follow the themes and strands and see how their work contributes to the development of the field. Language and the Joint Creation of Knowledge draws on the most prominent writing of Neil Mercer, covering his ground-breaking and critically acclaimed work on the role of talk in education, and on the relationship between spoken language and cognition. The text explores key themes, relating theoretical ideas to research evidence and to practical educational situations that improve children’s lives. Offering students and researchers a clear, accessible and up-to-date account of a sociocultural perspective on the relationship between spoken language and cognition, it explains one of the key themes in Neil Mercer’s work – that humans have uniquely evolved the capacity to think together, or ‘interthink’. Offering a crucial insight into the work of Neil Mercer, this selection showcases why his approach has become the dominant paradigm in educational research, and why it is increasingly influential in the psychology of teaching and learning. This unique collection of published articles and chapters, which represent the key themes and range of his research over the last 40 years, will be of interest to all followers of his work and any reader interested in the role of language in education.