This document introduces personas and how they can be used in user interface design. It defines personas as fictional representations of actual user groups that are created based on real user data. The document then describes a six-step process for creating personas, which includes identifying data sources, categorizing users, collecting user data, prioritizing user categories, developing persona foundations, and designating persona types. It provides an example of how personas can be applied in a product planning meeting to help envision design opportunities based on the needs and goals of the persona.