I am listening to the audiobook of
Raven Rock: The Story of the US Government's Secret Plan to Save Itself While the Rest of Us Die.
Sensational title aside, it's a very good book on the Continuity of Government planning during the Cold War. I think it's a worthy successor to
The Day After World War III, and it gives a better historical background than the latter.
The information on the state lines of succession are more than a little interesting.
To say this is required reading for Twilight: 2000 referees is an understatement. I give it 4 out of 5 mushroom clouds.