Scarlett O'Hara is definitely one of the first anti-heroines.
Well, not quite true since a lot of her character is taken from Thackeray's Becky Sharp, the principal opportunist in his 1848 epic comic novel VANITY FAIR, as is a lot of the novel of GONE WITH THE WIND, something Margaret Mitchell never wanted to admit. Much as I want to like the humor of VANITY FAIR, I think it's a dreadfully long bore and GONE WITH THE WIND a much more entertaining read.
I read VANITY FAIR in grad school when I was hospitalized with the flu for a week and I took it with me since I knew it would force me to read it if i had no other book. It's first chapters, with Becky, the over-sugary Amelia (not far stretch from the name Melanie), the mean old maid headmistress, her kindly wimp of a sister and Dr Johnson's dictionary, is outrageously funny, and you think, this book will be as good as Jane Austen, About ten chapters later, you realize you were wrong, and then we finally get to the Battle of Waterloo and the adventures of escaping from Brussels, which is aboslutely gripping and as fantastic as Miss Mitchell's use of it to escape Atlanta. After that, the novel plods along to its happy ending for Amelia and tragic ending for Becky, while Miss Mitchell keeps all her plot like Ol Man River just rolling right along. I have always preferred the serializations of VANITY FAIR on PBS to the book. at one point I tried to reread it, loved the opening, and decided that was where the fun ended.