This document discusses the difference between proper nouns and common nouns. It explains that proper nouns name a specific person, place, or thing, like Kayley or Indiana, while common nouns refer to general categories, like girl or state. Proper nouns are always capitalized. Examples of proper nouns include names of people, days, months, holidays, cities, states, songs, books, movies, and titles like Dr. or Aunt. The document provides practice identifying proper nouns and correcting sentences that do not follow capitalization rules for proper nouns.