This document provides an overview of a lesson on genre theory. It introduces Steve Neale's theory that genres are dominated by repetition but also marked by difference, variation, and change. The lesson asks students to research conventions in television crime dramas, compare shows like Life on Mars to identify repetitions and differences, and explain how Neale's theory applies to the genre through examples. The goal is for students to understand how repetition and difference in television crime drama is important to audiences.