Not a book and not an overview, but this(1998_film) was a film that gave me a better idea of what happened in Lahore post-partition. It details the effect on a group of differently faithed young people after Pakistan and India are split and is very enlightening. One thing I have read elsewhere is that when Britain was leaving India, they just drew an arbitrary line down the country and that is why Kashmir is still in dispute.
Another work of fiction that is helpful is a novel called The Hindi-Bindhi Club which is a novel of mothers and daughters similar to The Joy Luck Club. It also gives a graphic description of some of the atrocities that were committed by both religious groups.