How does the format of THE PERKS OF BEING A WALLFLOWER help contribute to the exploration of Charlie's character? Do the letters help us to understand Charlie and his relationships to friends and family better? Why or why not?

Letters are personal by nature, even confessional. This format works well for the themes and tone of the book. Check out the link below and you will see how the letters lend themselves to exploration of identity: especially for Charlie who is an expressive writer. teen angst, coming of age is a good match for this genre.

https://www.gradesaver.com/the-perks-of-being-a-wallflower/study-guide/themes