Lady Susan
The epistolary novel had been popular in the 18th century, but it was not the best style of writing for Jane Austen's talents (which is why all her major novels were written in the third-person narrative style). She admired Richardson very much (all of his books are written in letters, like Pamela (novel) and Clarissa (novel)), and she also admired Frances Burney's style, but none of their styles came naturally to her. She pointed out at the end of Lady Susan: "This correspondence (letter-writing), by a meeting between some of the parties (people) and a separation between the others could not, to the great detriment of the Post Office...be continued longer."