Sula (1973) tells of the friendship between Sula Peace and Nel Wright.  Sula and Nel keep each other's secrets when they are young, but a betrayal between them when they are older could mean the end of their friendship.

Once again, Toni Morrison packs so much emotion into such a short book.  Sula is less than 200 pages but I found myself rereading sections to savor the power of Morrison's descriptions.

I highly recommend reading the foreword of this book before reading.  It won't spoil anything, but the author gives insight into the opening chapters and how she would have changed it.