I doubt that I'll write any sort of review of Emma, but wanted to mention a few things that have made this reading special for me. I warn you now, that there will be spoilers in this post, so if you haven't read Emma, you might want to look away.
I purchased this book, Jane Austen, The World of Her Novels by Deidre Le Faye a few years ago.

It was one of those book that I just had to have right now but of course, years have passed, and while I've browsed this book many times, I've never properly read it. The second part of this book features chapters on each novel, with fairly extensive plot descriptions as well as commentary. The plot descriptions are rather lengthy but have been useful for me in perhaps pointing out things that I missed.
The author mentions something I've read or heard before, that is, that Jane Austen considered Emma a character 'whom no one but myself will much like' and I think that is really true. Emma is truly a difficult character to like. She is attractive and rich and appears to think herself much better than other people. I wonder if readers 200 years ago found this characteristic as unpleasant as I do now. Le Faye also mentions the fact that in Emma, Austen has created a detective story, that in fact 'the clues to the secret engagement between Frank Churchill and Jane Fairfax have been there all the time, but because Emma did not notice them, neither did we.' I have found great pleasure in seeking out these moment in the book that seem to point to one thing, when another thing is the truth. Frank Churchill is the cunning man in this novel, who is charming but dishonest, who we root for to start with and later wonder how we didn't see his true self.
This chapter on Emma ends with some thrilling revelations. Austen was obviously quite involved with and fond of the characters she created and we know this because she talked about the characters with her own family and what they were doing after the book ended. For example, Emma and Mr Knightley lived with Mr Woodhouse for about two years before they were free to live at Donwell. Jane Fairfax only lived 9 or 10 years after her marriage due to tuberculosis. She told them other little secrets and idea of future matches, and the fact that Mr Knightley was one of her two favorite characters, along with Edmund Bertram. Le Faye includes these sorts of insider tidbits for several of Austen's books making this book a must for Jane Austen fans.
