Persona Development is the skill of creating detailed, realistic profiles of your target users. A persona is a semi-fictional character representing a user type. It includes behaviors, motivations, pain points, goals, and frustrations. Personas guide design decisions (which features matter to which users), prioritize features (which personas' needs are highest-impact), and align teams (everyone designs for the same user type). Well-crafted personas feel real. You can imagine talking to them. "Alex, a busy product manager juggling five projects, frustrated by context-switching tools, looking for a single dashboard" is more useful than "busy professionals."