A single ship, a very large ship, was sighted. The dipped orders came rapidly -- ""Dive! Dive! Dive!"" followed by ""Main motors. Full power!"" In a wink, the U-boat skipper Kapitanleutnant Walther Schwieger -- ""unfortunate"" Schwieger -- had the target in his periscope. ""His brain ticked like a computer, measuring off angles, ranges and deflection."" Then ""First tube -- fire!"" Seconds later Schwieger's face went white -- ""My God. It's the Lusitania!"" German submarine power was felt around the world, the unpremeditated (as Gray tells it) sinking of the merchant vessel costing 2000 innocent lives and unleashing a time for killing on the high seas. Gray, whose first book A Damned Un-English Weapon (1971) offered an unsentimental account of British submarine warfare during the First World War, now records the battle operations and strategies of the German command, striving to maintain a ""similarly objective and impartial"" stance. Each encounter is dramatized for popular readability (Gray making good use of the verbatim recollections of former U-boat captains found in Lowell Thomas' Raiders of the Deep, 1929), but at all times the perspective remains neutral. Gray argues, for instance, that while it was true that the Kaiser and his Clausewitzian military planners waged a ""ruthless"" and ""unrestricted"" U-boat campaign against allied shipping in the latter years of the war, both the Royal and U.S. navies ""had adopted similar sink-on-sight tactics"" in defiance of international law and treaties, and that moreover the ""vast majority"" of U-boat commanders performed their ""distasteful task with humanity and chivalry."" This of course is not the typical history-book rendering of the U-boat war, but, like A. J. P. Taylor's on the war as a whole, Gray's version of German motives and limited culpability can withstand the most determined scrutiny.