The chapter discusses the limitations of the mainstream framework of information processing cognitive psychology in human-computer interaction (HCI) research and design, highlighting the gap between research findings and practical applications. It critiques the current state of HCI, noting that many successful solutions are not adequately explained by cognitive psychology and that practical designers often do not use research findings. The chapter introduces activity theory as a potential alternative framework, emphasizing its multilevel perspective, context sensitivity, and focus on development and dynamics. Activity theory, rooted in Soviet cultural-historical psychology, views activities as basic units of analysis, recognizing their historical development, mediation through artifacts, and the interplay between subject, object, and community. The chapter suggests that activity theory can help address the complexity of HCI by integrating different levels of analysis, considering the social context of interactions, and supporting the formation of new operations and actions. It concludes by highlighting the potential of activity theory to advance HCI research and design, particularly in supporting dynamic and developmental aspects of human practices.The chapter discusses the limitations of the mainstream framework of information processing cognitive psychology in human-computer interaction (HCI) research and design, highlighting the gap between research findings and practical applications. It critiques the current state of HCI, noting that many successful solutions are not adequately explained by cognitive psychology and that practical designers often do not use research findings. The chapter introduces activity theory as a potential alternative framework, emphasizing its multilevel perspective, context sensitivity, and focus on development and dynamics. Activity theory, rooted in Soviet cultural-historical psychology, views activities as basic units of analysis, recognizing their historical development, mediation through artifacts, and the interplay between subject, object, and community. The chapter suggests that activity theory can help address the complexity of HCI by integrating different levels of analysis, considering the social context of interactions, and supporting the formation of new operations and actions. It concludes by highlighting the potential of activity theory to advance HCI research and design, particularly in supporting dynamic and developmental aspects of human practices.