Question

I need help writing an introduction for a compare-and-contrast analysis of how Greg Ridley from “The Treasure of Lemon Brown” changes from the beginning of the story to the end.

Answer 1

 I've never read this but i'd suggest if you haven't already comparing and contrasting what happened at the beginning and what happened throughout and the end. Make sure these are important details. You can include some that aren't important as well. 
 As for an introduction something simple like, "Many experience changes throughout their life this is about the changes throughout (insert main character's name)'s life".