Reaping the Whirlwind, The U-boat War off North America during World War I, Schiffer Publishing, Ltd., Schiffer Military History,Naval forces and warfare,Military forces and sectors, Whirlwind; 1917; Submarine Warfare; German Archival Sources; Author Dominic Etzold; North American Coast; Revelatory Account; English-language Histories; Declared War; Unrestricted Submarine Warfare; Resumption; Intense Period; u boat; subs; submarine; imperial germany navy; wwi; great war; battle of the atlantic; ww1; merchant marine,, , United States, en-UShttps://schifferbooks.comWhirlwind; 1917; Submarine Warfare; German Archival Sources; Author Dominic Etzold; North American Coast; Revelatory Account; English-language Histories; Declared War; Unrestricted Submarine Warfare; Resumption; Intense Period; u boat; subs; submarine; imperial germany navy; wwi; great war; battle of the atlantic; ww1; merchant marine, [BLURB],[CITY],,books, ebooks, biblet, Book2look