The contributors to Developmentalism in Early Childhood and Middle Grades Education: Critical Conversations on Readiness and Responsiveness challenge dominant discourses and practices in the fields of early childhood and middle grades education that are based on the last century’s grand developmental theories. Editors Kyunghwa Lee and Mark D. Vagle and the other contributors examine the notion of development in their own work by employing various alternative frameworks, including Bakhtinian ideas, Buddhism, cultural psychology, and post-structuralism. Exploring issues related to developmentalism within and across the fields, the contributors invite the reader to participate in the cross-field dialogue which provides new language and perspectives for the education of young children, young adolescents, and teachers in both fields.