Complex sentence: A 310 page unpublished manuscript Parfit has been working on for at least 15 years which though it has been widely circulated throughout the professional philosophical community, it is not known when it will be published.
Split into simpler sentences: A 310 page unpublished manuscript Parfit that has been working on for at least 15 years. Although it has been widely circulated throughout the professional philosophical community, it is not known when it will be published.