An understanding of psychology-specifically the psychology behind how users behave and interact with digital interfaces-is perhaps the single most valuable nondesign skill a designer can have. The most elegant design can fail if it forces users to conform to the design instead of working within the "blueprint" of how humans perceive and process the world around them. This practical guide explains how you can apply key principles of psychology to build products and experiences that are more human-centered and intuitive. Author Jon Yablonski deconstructs familiar apps and experiences to provide clear examples of how UX designers can build interfaces that adapt to how users perceive and process digital interfaces. Since the first edition of this book, LLMs (Large Language Models) have undergone significant advancements, AI-powered image generation tools have emerged, spatial computing has entered the mainstream, and smartphones have become even more powerful. However, the principles and concepts covered in this book remain timeless, and they provide a solid foundation for every designer, regardless of their level of expertise. To enhance the reader’s experience, the second edition includes additional information linking these principles and concepts to psychology concepts, techniques, and key considerations.