Which books could be compared with dr jekyll and mr hyde?

A Tale of Two Cities is a great example. Two men that look very similar but are moral opposites fall in love with the same woman. As their morals and love is tested, Charles ens makes comments about personal morals and societal standards. It's a pretty easy read, but there are also movie versions and several study guides available. It's the "it was the best of times, it was the worst of times" novel.