Soon after the novel became a best-seller, apparently, but I haven't seen it and can't really imagine it - so much depended on the spelling mistakes and little drawings the students put on their suggestion box messages or notes passed in class, the imperious directives from the administration, a few actual letters, etc. I've seen an adaptation of Richardson's "Clarissa," so I know that letters are not actually required to tell a story, but in this case, I just don't think it would be a good thing.