Those Who Leave and Those Who Stay by Elena Ferrante
I consider David Copperfield to be a great book, one of many masterpieces by Charles Dickens. It’s a long book, a very long book, telling nearly the entire life story of its narrator and title character.
People may prefer different sections of David Copperfield over other parts of the book, the bits with Francis Micawber are the best parts by the way, but you can’t really judge the book as anything other than one work. You don’t have four opinions, one per quarter; you have one opinion.
I think that’s the best way to read Elena Ferrante’s Neapolitan Novels. They have been broken down into four separate books but they are really one novel. The cast of characters introduced in the first book has not grown much by the end of book three, Those Who Leave and Those Who Stay. The issues the main characters face are still basically the same, the conflicts introduced in childhood continue to haunt the 
narrator’s life in book three. This is a life story; life goes on.
I’ve finished reading book three and plan on completing the series sometime this summer or in the early fall. I feel like I should just post a link to my earlier reviews, or maybe invite you to come back later when I’m done with all four and can try to make sense of them in a more complete way.
Until then I can say that I’m still loving the books, enthralled by the characters, hoping they can work things out somehow. I’ve no idea how all of this will end and I’m not exactly looking forward to it. When you spend this much time with a character, it can be hard to say goodbye.