My Shapard-annotated Sense and Sensibility has a note in the introduction that gives me pause.

[…] D. W. Harding, has argued […] that this initial version [of Sense and Sensibility] was not in the form of letters. He reasons that the final version […] devotes less space to letters than most of Jane Austen's novels, and, since there is no character to function as the recipient of a continual and frank correspondence from the main character, Elinor, it is difficult to see how this story as it now stands could have been told in this manner. Instead he guesses that the sole source for this idea, Caroline Austen -- whose brief memoir My Aunt Jane was composed more than fifty years after Jane Austen's death and relied on what she heard from others for the subject's early life -- confused Elinor and Marianne with the initial version of Pride and Prejudice […] . The latter novel is a much better candidate for an original epistolary composition, since the completed version employs letters heavily, far more than any other Austen novel, and provides the heroine with two characters, her sister and her aunt, who together could have received her correspondence over the course of the novel.

I had accepted that both novels had been first written as letter-exchanges, and I have even based some guesses on that. But the Harding supposition sounds so plausible to me, that I think I have changed my mind. As the novel goes on, I am going to keep an eye out for likely letter-written moments, and problems with any such format, both. I would appreciate it, if the others in this Group Read share anything that occurs to them, too.

I am sorry this book did not come in time for me to use it to begin the Group Read, but I am enjoying it immensely so far! I will post ideas culled from it, and (no doubt) places where I disagree with Dr. Shapard's opinion (as I am pretty opinionated my own self). I know others are using other annotated versions, and, possibly, other source books. I hope we all keep posting when inspired by text adjunct to Author Austen's!