Foundations of Human-Computer Interaction: Designing for Cognitive Alignment reframes human-computer interaction (HCI), usability, and user-centered design by focusing on the conditions under which cognition stabilizes over time. It provides an integrated account of HCI by bringing together cognitive science, neuroscience, and design principles to explain how systems shape perception, regulate attention, and support stable reasoning across repeated encounters. This approach ensures that graduate and undergraduate students not only understand core theoretical frameworks but also recognize how design decisions influence reasoning, decision-making, and cognitive effort in real-world contexts. The book emphasizes structured learning and iterative design processes, making the material accessible to both novices and advanced learners. It also addresses contemporary challenges such as AI-driven systems, adaptive interfaces, and large-scale personalization, offering a framework for understanding how misalignment emerges as instability—seen in repetition, delayed decisions, fragmented attention, and unresolved effort—and how design can support clarity, recovery, and trust in responsible ways