Why are things so hard to use these days? Why does not this thing I just bought work? Why is this web site so hard to use? Why are users not liking my design? Why is my app not getting popular? These are frustrations that we have all faced from systems not designed with people in mind. The question this course will focus on is: how can we design human-centered systems that people find useful and usable? This course is an introduction to designing, prototyping, and evaluating user interfaces. If you take only one course in Human-Computer Interaction, this is the course for you. This course is heavily inspired by the course that Prof. Jason Hong teaches at CMU, Designing Human-Centered Systems.