carol anderson, thank you very much. carol: thank you. [applause] [captions copyright national cable satellite corp. 2015] [captioning performed by the national captioning institute, which is responsible for its caption content and accuracy. visit ncicap.org] announcer: you are watching ameren can history tv -- american history tv all weekend on c-span 3. to join the conversation, like a fun piece -- like us on facebook. tonight on q&a, eric larson on his new book "dead wake." larson: the story gets complicated when the question arises that what ultimately happens to the lusitania? why was the lusitania allowed to enter the irish sea without escort, without the kind of detailed warning that could have been provided to captain william thomas turner but was not? and this has led to some their interesting speculation about was the ship set up for attack by churchill