Here's a few more to add to the reading list:
"The Kingdom of the Cults", and "Jehovah of the Watchtower" by Walter Martin
"The Four Major Cults" by Anthony Hoekema
"When Prophecy Fails" by Leon Festinger et al. This is an academic study of a UFO cult's failed prophecy and its effect on believers. Although not directly related to the Watchower it explains a lot about why believers stick with it.