I can’t add much to the positive reviews already posted. What I found fascinating was Mr. Larson’s description of the German U boats: their construction, operation, life on board, and action in battle. Using a dual narrative, following both the sailing of the Lusitania and the sea voyage of U-20 helped increase the tension of what you know is coming. I believe some reviewers felt Mr. Larson didn’t give as much detail on 3rd class passengers, or even 2nd class passengers. True, he wrote most completely about the 1st class voyagers but, in fairness, in those days 3rd class passengers were not worthy of notice by anyone and it may have been hard to get any information about them. I felt there was a fair mix of the 2nd class people. The story of Room 40 was also very interesting and has stoked my interest to find out more. All in all, I thoroughly enjoyed the book and was hard pressed to put it down when my real life intruded from time to time !!