The Romance genre is a category of fiction that focuses primary attention on the relationship and romantic love between two people. While romance elements can appear in many books, a story is generally classified as a "Romance" only if it meets two specific criteria:

1. The Central Plot: The main story revolves around the developing relationship and the emotional journey of the protagonists. Every other subplot (like a mystery or a career goal) remains secondary to the romance.

2. The Optimistic Ending: A defining rule of the genre is that it must have a "Happily Ever After" (HEA) or a "Happy For Now" (HFN). If the lovers do not end up together, the book is usually classified as a Love Story or Tragedy rather than a Romance.