The article by Wolff-Michael Roth and Yew-Jin Lee explores the cultural-historical activity theory (CHAT), a theoretical framework that has been largely overlooked in academic circles. Originated by Lev Vygotsky, CHAT was further developed by his students and followers, particularly A. N. Leont’ev, into a comprehensive theory that integrates societal, cultural, and historical dimensions into the study of human mental functioning. The authors argue that CHAT offers a holistic approach to understanding learning and education, addressing the gaps between theory and practice, and providing a framework for overcoming common educational challenges. The article begins by highlighting the limitations of traditional educational psychology, which often separates intellect from affect and treats psychic processes in isolation. This approach, criticized by Vygotsky and his students, fails to capture the full complexity of human experience and learning. The authors illustrate these issues through a vignette about a fifth-grade teacher, Katherine, who faces the challenge of teaching electrical circuits to her students. Despite her efforts to create meaningful, hands-on learning experiences, she is pressured to adopt a more traditional, direct teaching method due to accountability pressures. To address these challenges, the authors introduce CHAT, which views learning as an expansion of action possibilities in pursuit of motives and goals. This perspective emphasizes the importance of context, social interaction, and the mediation of activities by society. CHAT is described as a dialectical theory that allows for the understanding of complex, non-living entities like classrooms, school departments, and workplaces as performing acts of learning similar to individuals. The article also discusses the historical development of CHAT, its influence on Western scholarship, and its application in various fields such as educational technology, literacy research, and communication studies. It highlights the importance of CHAT in addressing the tensions between individual and collective, material and mental, biography and history, and praxis and theory. The authors provide a detailed explication of CHAT's core concepts, including the "activity triangle" and the network of activity systems, and illustrate these with a case study of an environmental unit designed for seventh-grade students. Finally, the article emphasizes the potential of CHAT to transform educational research and practice by providing a more integrated and holistic approach to understanding and improving learning outcomes.The article by Wolff-Michael Roth and Yew-Jin Lee explores the cultural-historical activity theory (CHAT), a theoretical framework that has been largely overlooked in academic circles. Originated by Lev Vygotsky, CHAT was further developed by his students and followers, particularly A. N. Leont’ev, into a comprehensive theory that integrates societal, cultural, and historical dimensions into the study of human mental functioning. The authors argue that CHAT offers a holistic approach to understanding learning and education, addressing the gaps between theory and practice, and providing a framework for overcoming common educational challenges. The article begins by highlighting the limitations of traditional educational psychology, which often separates intellect from affect and treats psychic processes in isolation. This approach, criticized by Vygotsky and his students, fails to capture the full complexity of human experience and learning. The authors illustrate these issues through a vignette about a fifth-grade teacher, Katherine, who faces the challenge of teaching electrical circuits to her students. Despite her efforts to create meaningful, hands-on learning experiences, she is pressured to adopt a more traditional, direct teaching method due to accountability pressures. To address these challenges, the authors introduce CHAT, which views learning as an expansion of action possibilities in pursuit of motives and goals. This perspective emphasizes the importance of context, social interaction, and the mediation of activities by society. CHAT is described as a dialectical theory that allows for the understanding of complex, non-living entities like classrooms, school departments, and workplaces as performing acts of learning similar to individuals. The article also discusses the historical development of CHAT, its influence on Western scholarship, and its application in various fields such as educational technology, literacy research, and communication studies. It highlights the importance of CHAT in addressing the tensions between individual and collective, material and mental, biography and history, and praxis and theory. The authors provide a detailed explication of CHAT's core concepts, including the "activity triangle" and the network of activity systems, and illustrate these with a case study of an environmental unit designed for seventh-grade students. Finally, the article emphasizes the potential of CHAT to transform educational research and practice by providing a more integrated and holistic approach to understanding and improving learning outcomes.