I knew nothing about the Lusitania other than that it drew the US into the war. Larson's descriptions of the luminaries on board, as well as some of the cargo were very telling - although I felt the more he went into depth on particular characters, the more unlikely they were to survive - it did not make for comfortable reading. The descriptions of the U-Boat fleet and the captains of such boats reminded me very much of the types of incidents we are seeing today on the world's oceans. There are laws, but once out of earshot, the law is whatever the captain says it is.
It is odd to me how people who have been warned in one way or another that it is not a good idea to "board the ship" often ignore the waving flag and move forward ... then they are surprised when it all falls apart. There were so many people (both passengers and military) who didn't stop long enough to really look at the information they had, didn't stop to question anything, and people died because of it.