The original novel (Watchman) contains the same locale and many of the same characters who were teased out and turned into the novel To Kill A Mockingbird. This is what Ms. Lee's editor suggested. So yes, it is an evolution, from the earlier draft of a novel to the later completed novel that was Mockingbird. There are many who feel that this latest published but earlier written book should have remained buried. I'll finish reading it before I cast a vote one way or the other.